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What steps are taken to ensure those animals are fed adequately? When dealing with larger populations of animals, how is it ensured that all of those animals received food during a certain time period, and not fed multiple times by different people working different shifts? Is there a procedure in place for identifying and treating animals with over and under nutrition?
I volunteered for 3 years at a large mammal laboratory where we diligently tracked the weight and caloric intake of each of our animals. Diets were weighed out each morning and total calories could be calculated based on the known caloric value of the particular food item.
We fed our animals during training sessions and would adjust the individual's food intake based on their appetite/motivation (i.e. if an animal was full, they'd drop the piece of food they earned or leave the session). This would indicate that we could decrease the individual's diet in small increments.
The animals were also weighed each week. Weight and caloric intake were recorded in daily logs using FileMaker Pro. This allowed us to view fluctuations of each throughout the year and compare to previous years. If an animal's weight was a bit lower at a certain time of year than it typically was in past years, we could increase their diet.
Diet items were selected based off of the animals' natural diet.
In our university, this is regulated by Institutional Animal Care and Use Committee
This organization provides guidance for humane and responsible management of laboratory animals. These protocols were established, and still modified, to enable optimal well-being of animals, as researchers extremely interested in robust and stable conditions for their subjects.
On the practical note, (we work with fish) we monitor such parameters as: - efficiency of laying eggs - average size and time to adulthood (sexual maturity) - life span - rate of malformation or illnesses
The food is monitored and regulated to make these optimal, but we change these things gradually, and usually use some smaller population to test changes, before applying to whole colony.
Want to work in a zoo?
Zoos, Wildlife/Safari parks and special collections are run by Zoological Societies, Charitable Trusts, Local Authorities or as private enterprises. Zookeepers are responsible for the day-to-day care and welfare of animals kept in these environments.
The primary role of zookeepers working in a zoo is to ensure that these animals are kept physically and psychologically healthy. Zoo keepers need to be: enthusiastic about animals, interested in animal biology, patient with both the public and animals, have a pleasant friendly manner and good spoken communication skills. They need to be observant, reliable and punctual, physically fit, safety-conscious, have basic computer skills and a driving license for safari parks. It helps to be interested in animal biology, wildlife habitats and animal behaviour.
The Zoo Animal Care, Behaviour and Welfare Diploma course has been specifically designed as relevant Zoo Keeping training and includes information about care, behaviour, psychology, enrichment, welfare, conservation, rescue & rehabilitation of wild animals.
Zoo Keepers carry out tasks such as 'mucking out', cleaning and filling water troughs, replenishing bedding and monitoring temperatures. They are responsible for checking enclosures and may carry out maintenance jobs such as repairing fences. Zookeepers order food and bedding and ensure animals are fed according to their individual needs. Another important aspect of the work involves observing animals for any signs of injury or illness if an animal is sick or injured, zookeepers help with care under the direction of a vet. Zookeepers maintain healthcare records and as part of a research project, they may keep detailed records of an animal's activity or behaviour. Keepers answer visitors' questions and may give short talks or presentations. Keepers also make sure visitors do not feed or upset the animals or, particularly in wildlife parks, put themselves in danger by approaching animals too closely. In wildlife parks where animals live in conditions similar to the wild, Keepers will have less contact with the animals. In some cases, Keepers may be involved assisting with the design of new living quarters.
As confined animals are dependent on people to care for them, there is a need for staffing every day of the year, Keepers work on rota systems to cover all periods and more senior Keepers may be on a call-out rota, which could include evenings. Zookeepers may work outside or indoors, depending on the animals they care for. Conditions may be wet, cold, dirty, muddy, hot or humid. Keepers wear a uniform, normally an overall that is supplied by their employer.
With over one hundred million people visiting zoos every year, workers have an excellent opportunity to educate large numbers of people about the need for the conservation of wildlife and the importance of respecting animals. Working as a zookeeper assures a varied, interesting and rewarding career.
We encourage our students to set their career goals early for real life experiences in the field. This prepares them for entry into the workforce and enhances their coursework and career options.
Students in the Zoo & Aquarium Science concentration must complete a full semester internship at a zoo or aquarium. These internships are professional work experiences that take place under the supervision of experienced professionals. Students typically complete internships as juniors or seniors.
Student interns are expected to become familiar with the day-to-day operations of their host facility and interact with staff and visitors whenever possible. Most host facilities expect interns to be knowledgeable of recent advances in their science.
Benefits of an Internship
- Merges the student's academic background with the practical work necessary for the host facility to achieve its goals
- Help produce the foundation for a background in the zoo & aquarium industry
- Develop interpersonal and communication skills
- Learn how subunits within an administrative facility interconnect to achieve common goals
"I was able to do mostly everything a keeper would do in their day-to-day activity. The internship allowed me to expand on what I had learned through school and previous animal care experiences." Lincoln Park Zoo Intern
"I think that the skills that I developed by learning from the keepers and working alone will help me at the start of my zoo career. It gave me a higher level of confidence in my ability to work alone with the animals and my ability to make decisions." Zoo Montana Intern
"Watching the way employees interact with each other and with management taught me volumes I have been so focused on the animal aspect of my major that I had forgotten the human element. The human element is one of the hardest parts of a zookeeper's job." Potter Park Zoo Intern
MSU has partnered with the San Diego Zoo Global Academy to integrate the Academy's e-learning modules into the classroom.
IBIO 390: Careers @ the Zoo
Work alongside staff in every profession at Binder Park Zoo: Animal care, animal health, education, exhibit design and construction, horticulture, physical plant, business, marketing, guest services, and conservation.
Frequently Asked Questions
What is the best major for admission to veterinarian school?
Most veterinarian students major in biology. If you major in biology at Mississippi College, you will need to pursue the medical sciences career tract. Most veterinarian schools also require one semester of biochemistry and microbiology.
What kind of education is required to be a veterinarian?
Prospective veterinarians must graduate from a 4-year program at an accredited college of veterinary medicine with a Doctor of Veterinary Medicine (D.V.M. or V.M.D.) degree and obtain a license to practice. In addition to satisfying preveterinary course requirements, applicants must also submit test scores from the Graduate Record Examination (GRE), the Veterinary College Admission Test (VCAT), or the Medical College Admission Test (MCAT) depending on the preference of each college.
What type of prerequisites do veterinarian schools require?
Requirements vary among schools. The following are the requirements for the Mississippi State University College of Veterinary Medicine
- Minimum 2.80/4.00 overall
- Minimum 3.00/4.00 in required math and science courses
- Average overall GPA for 1999 entering class: 3.61/4.00
- VCAT (Veterinary College Admissions Test) or
- GRE (Graduate Record Exam) is required for admissions.
No minimum score required.
- 50% Academics
- 15% Application (written materials)
- 5% Confidential Evaluations
- 10% VCAT/GRE
- 20% Admissions Interview
Physical Sciences (18 hours)
- 4 hours: Chemistry I with lab
- 4 hours: Chemistry II with lab
- 4 hours: Organic Chemistry I with lab
- 3 hours: Elementary Biochemistry
- 3 hours: Trig-based Physics with lab
Mathematics (6 hours)
Any mathematics course equal to or higher in level than College Algebra is acceptable.
Nutrition (3-5 hours)
Must be biochemistry based animal or human nutrition course.
Humanities, Fine Arts, Social Sciences, Behavioral Sciences (15 hours)
Biological Sciences (14 hours)
- 4 hours: Vertebrate Zoology with lab
- 4 hours: Microbiology with lab
- 3 hours: Cell Biology
- 3 hours: Genetics
Total Required Hours: 65-67 hours
What kind of courses will I be taking in veterinary school?
The Mississippi State University College of Veterinary Medicine offers a 4-year professional curriculum leading to the Doctor of Veterinary Medicine (D.V.M.) degree. The fundamental goal of the program is to develop graduates with skills and behaviors necessary to foster lifelong learning and a career of service managing animal health and disease. The first two years of the program (Phase 1) are presented by the problem-based learning (PBL) method. Students utilize the resources of the college to solve simulated animal problems in a guided independent study of basic and clinical sciences. The second two years (Phase 2) of the curriculum place students in the Animal Health Center where they are directly involved in patient care. After successfully completing required clinical rotations, students design a personal program of study that emphasizes their interests in one or more of the specialized aspects of veterinary medicine.
Details on application for admission and entrance requirements are available from the Office of Student Affairs, College of Veterinary Medicine, P.O. Box 9825, Mississippi State, MS 39762, phone (662) 325-1129.
What is VMCAS?
The Veterinary Medical College Application Service, or VMCAS, is sponsored by the AAVMC and serves as a central place for the distribution and processing of applications to veterinary medical schools. Most veterinary schools use the service, which allows you to file one application and have it distributed to the participating schools in which you're interested. VMCAS is a processing service. It does not set application requirements or deadlines, and is not involved in making admissions decisions. You must discuss those issues with the schools you're interested in.
PO Box 24700
Oakland CA 94623-1700
Telephone: (510) 873-8180
TDD: (510) 510-465-5571
What do veterinarians earn?
According to the Bureau of Labor Statistics, the yearly median pay for veterinarians was $84,460 in 2012.
Lab 5: Flatworm and Smaller Lophotrochozoans
Phylum Rotifera: rotifers
Phylum Acanthocephala: spiny-headed worms
Phylum Ectoprocta (Bryozoa) &ndash &ldquomoss animals&rdquo (Bugula, Plumatella)
Phylum Brachiopoda &ndash &ldquolampshells&rdquo (Lingula, Terebratella)
Phylum From this point on, all animals covered in the Zoo Lab website have primary bilateral symmetry and are triploblastic, that is, three true germ layers (the ectoderm, mesoderm and endoderm) are formed during gastrulation of the blastula stage of development. While radial symmetry may be well suited for sessile or slow-moving forms, animals that are active in seeking food, shelter and mates require a new body plan. Bilateral symmetry coupled with cephalization solves these problems. The anterior end moves forward and the posterior follows. The dorsal side is kept facing up and the ventral side is kept down and usually specialized for locomotion.
The bilateral grade of metazoans is further subdivided into two main divisions: the protostomes and deuterostomes, which are separated on the basis of a number of embryological differences. Evidence from sequence analysis of the small-subunit ribosomal gene suggests that some time after ancestral deuterostomes and protostomes diverged from one another during the Cambrian period, protostomes split into two large groups (superphyla), the Ecdysozoa and Lophotrochozoa. In this lab we will examine one acoelomate lophotrochozoan phylum and several smaller pseudocoelomate and eucoelomate lophotrochozoan phyla.
The Phylum Platyhelminthes contains over 20,000 free-living and parasitic species of acoelomate animals called flatworms. In flatworms, the body that is flattened dorsoventrally, with the mouth and genital pore usually located in a ventral position. The space between the gut and outside is filled with mesodermal muscle fibers and undifferentiated parenchyma. Although fluid-filled spaces in the parenchyma serve as a hydrostatic skeleton for support and to aid in internal transport, the animals lack a body cavity, which is why they are called acoelomate. Most free-living flatworms have a gastrovascular-type digestive system (a mouth is present but no anus), while parasitic forms generally have no digestive system.
Flatworms have a centralized nervous system consisting of pair of cerebral ganglia and longitudinal nerve cords connected to transverse nerves. The excretory system (absent in some forms) consists of two lateral canals with protonephridia bearing flame cells. Although many flatworms are free-living, the phylum includes some very important parasitic species as well.
In terms of reproduction, flatworms can reproduce sexually or asexually. Most species are monoecious but practice cross fertilization. Many freshwater turbellarians can reproduce asexually by fission in which the animal simply divides into two halves, each of which regenerates the other half. In some turbellarians (as it is in most other animals), the yolk that provides nutrition for the developing embryo is containing within the egg cell itself, a condition described as endolecithal. In the monogeneans, trematodes and cestodes (as well as in a few turbellarians), yolk is contributed by cells released from organs called yolk glands, and the eggs are therefore described as ectolecithal. Development may be direct or indirect.
The Class Turbellaria contains mostly free-living forms ranging in size from a few mm to 50 cm. Most species are bottom dwellers in marine and freshwater environments that crawl over rocks, sand or vegetation. Smaller forms can swim by means of ventral cilia, but more often they move by laying down a sheet of mucus that aids in adhesion and helps the cilia gain traction. Larger forms use powerful muscle contractions to crawl or swim. Unique to turbellarians are rod-shaped rhabdites found among the ventral epidermal cells of the body surface. These rhabdites secrete mucus that coats the animal's body, possibly for protection against predators or to prevent drying.
In terms of nutrition, most turbellarians are predators and scavengers. Epidermal mucous secretions trap and kill prey items. A muscular pharynx everted though the ventral mouth is used to secrete digestive enzymes into prey, which is then sucked into the branched intestine that forms a gastrovascular cavity. In addition to a simple nervous system, turbellarians have light-sensitive eye spots called ocelli that help orient the animal to the direction of light. Touch and chemical receptors in some forms like the planarian seen in lab are concentrated in lateral projections from the head called auricles that look like ear lobes. Reproduction in turbellarians can occur asexually through fission or sexually all forms are monoecious but practice cross-fertilization. Planarians are also known for their tremendous powers of regeneration, and a planarian that has been cut into three pieces will give rise to three new complete individuals!
The Class Monogenea contains animals called monogenetic flukes. Although most of species are ectoparasites on the skin or gills of fish, there a few forms found in the bladders of frogs and even one that lives in the eye of a hippopotamus! The life cycle of a monogenetic fluke is direct, with a single host. Since they must depend on a single host for both reproduction and transmission, monogenetic flukes have evolved mechanisms that usually ensure that the parasites do not endanger the lives of their hosts, but in crowded conditions (such as fish hatcheries), they can produce serious, damaging infestations.
The Class Trematoda contains about 8,000 species of leaf-like animals called digenetic flukes. The adults are endoparasites on vertebrates but many invertebrates serve as intermediate hosts, and many species of medical and economic importance! Development is trematodes indirect not only adults but larvae reproduce and all species have at least two hosts, one for transmission and the other for reproduction. The vast majority of flukes possess two large suckers that are used for attachment, an anterior one called an oral sucker, which surround the mouth and a posterior one called a ventral sucker, or acetabulum.
In trematodes, one egg leads to the production of many progeny! Eggs are typically deposited in water via the urine or feces of the definitive host. When they reach freshwater, the egg opens and a ciliated free-swimming larva called a miracidium swims out. The miracidium will then swim about until it finds a suitable intermediate host, which is usually an aquatic snail to which it is chemically attracted. When the miracidium finds snail, it penetrates it, loses its cilia and develops into a sporocyst, which produces asexually either more sporocysts or a number of rediae that also produce asexually either more rediae or tailed forms called cercariae. The cercariae emerge from the snail, swim around and penetrate a second intermediate host, the final (definitive) host or encyst on vegetation (in the case of the sheep liver fluke), where they are transformed into metacercariae, which are juvenile flukes the adult grows from the metacercariae when it is eaten by the definitive host.
Trematode Infection in Humans
Humans can be infected with a number of serious trematodes in a variety of ways. In the case of the Oriental liver fluke (Clonorchis sinensis), infection occurs by eating raw or poorly cooked fish (which serve as the second intermediate host of the parasite) containing the metacercariae of the trematode.
In the case of blood flukes (Schistosoma), infection can occur when tailed cercariae burrow through exposed skin of people bathing or working in waters containing the cercariae (such as Asian rice paddies). Schistosomiasis is a chronic illness that can damage internal organs and, in children, impair growth and cognitive development. The urinary form of schistosomiasis is associated with increased risks for bladder cancer in adults, and the disease is the second most socioeconomically devastating parasitic disease after malaria!
The sheep liver fluke (Fasciola hepatica) is a common parasite of sheep and cattle, which become infected by eating aquatic plants containing encysted metacercariae (juvenile flukes). Humans can acquire the parasite by eating raw watercress (which grows naturally at the edges of lakes and ponds and is cultivated in many countries in Asia and Europe) containing the metacercariae of the fluke.
The lung fluke (Paragonimus westermani) is a potential dangerous parasite found in Asia and South America that can cause death in human hosts. Their eggs are coughed up from the lungs of their host, swallowed and eliminated in feces Humans can become infected by eating raw or poorly cooked freshwater crabs (the second intermediate host of the parasite) containing the metacercariae of the fluke.
The Class Cestoda contains about 4,000 species of tapeworms, all of which are highly modified endoparasites that live in just about every known vertebrate species. The long, flattened body of a tapeworm (which is referred to as the strobila) is divided into segments called proglottids. Most forms have an organ called a scolex at the anterior end with suckers, hooks, etc. that attach to the wall of the gut and prevent them from being swept away.
Tapeworms lack a digestive system and feed by absorbing nutrients directly from the host. The entire body surface is covered with minute projections called microtriches that greatly increase the absorptive surface area of the tapeworm. Tapeworms also secrete substances that inhibit the digestive enzymes of their host as well as lowering the pH around them to a level that they but not the digestive enzymes of their host can function. In tapeworms, much of the strobila is given over to reproduction. Each proglottid is monoecious, and cross-fertilization or even self-fertilization is common. Proglottids can be filled with up to 100,000 eggs!
With few exceptions, all cestodes require at least two hosts, and the adult is the parasite in the digestive tract of vertebrates. Often one of the intermediate hosts is an invertebrate (most often an arthropod such as a flea, louse or copepod) that is eaten by the final host. The eggs within the proglottids are shed daily in the feces into the soil where they may lie dormant for quite some time. Sometimes the egg-bearing proglottids crawl out of the anus by themselves and can be found wriggling about on an infected dog, cat or child or on infected clothing and bedding. Once the eggs are released, they must be ingested by an intermediate host in order to hatch into hooked larvae called oncospheres, which bore through the intestinal wall and picked up by the circulatory system where they are transported to skeletal muscle, heart or even some other organ where they encyst as cysticerci (bladder worms). Each cysticercus is essentially an inside-out scolex that everts after the infected tissue (so-called &ldquomeasly meat&rdquo) of the intermediate host is eaten by the final host. The scolex then attaches to the lining of the intestine by means of suckers and/or hooks.
Tapeworm Infection in Humans
Humans can become infected with tapeworms by eating poorly cooked meat containing the cysticerci of the tapeworm. The most important tapeworms that infect humans are the beef tapeworm (Taenia saginata) and the pork tapeworm (Taenia solium).
Another species of cestode that can infect humans is the broad fish tapeworm (Diphyllobothrium latum), which is common in fish inhabiting the Great Lakes. Again, infection occurs by ingesting cysticerci in raw or poorly cooked fish. In most cases, tapeworms found in the gut do not cause much damage to their human hosts, but occasionally they migrate to other organs such as the eyes or even the brain, where they can cause serious neurological problems and even death from cerebral cysticercosis!
The dog tapeworm (Diplydium caninum) is common in dogs but can be picked up by humans (usually kids) who ingest infected fleas that serve as intermediate hosts of the parasite.
In contrast to radiate and acoelomate phyla in which the space between the body wall and the digestive tract is filled with mesoglea or with solid mesenchymal parenchyma, the remaining bilateral animals covered in the Zoo Lab website have a body cavity in which internal organs are located. In the pseudocoelomates, the embryonic blastocoel persists as a body cavity. Since it is not lined with mesodermal peritoneum (the lining of the coelom), it is called a &ldquofalse cavity&rdquo or pseudocoel.
The Phylum Acanthocephala contains about 1,000 species of parasitic animals called spiny-headed worms, all of which are endoparasites in the intestinal tracts of vertebrates (especially fishes). Two hosts are required to complete the life cycle, and the juveniles are parasites of crustaceans and insects. Most species are quite small (less than 40 mm). Spiny-headed worms have an eversible proboscis covered with recurved spines that provides a means of attachment in the host's intestine. Eggs pass out host and are eaten by certain insects or crustaceans where they hatch and go through several developmental stages. When the intermediate host is eaten by a bird, mammal or fish, the larva inside attaches to the intestinal wall with its spiny proboscis.
The Phylum Rotifera contains about 1,800 species of microscopic animals called rotifers that bear an anterior crown of cilia that give the appearance of a revolving wheel. Although cosmopolitan (widely distributed), most are found only in freshwater environments. The general body plan of a rotifer is divided into three regions: a head, which bears a ciliated organ called a corona (wheel organ), which creates currents that draw small planktonic forms into the mouth, which opens into a muscular pharynx called a mastax. The mastax is equipped with intricate jaws composed of seven hard pieces called trophi that are used for grasping and chewing the prey. The trunk contains the visceral organs, and the foot (when present) is segmented and ringed into joints that can shorten or telescope. Pedal glands on the foot secrete a sticky substance that anchors the animal to the substrate or allows it to creep along with leech like movements.
From this point on, all animals that will be studied in the Zoo Lab website are eucoelomate, that is, they have a true coelom (body cavity) that is lined with a thin layer of mesodermal tissue called the peritoneum. Note: The development of the coelom must be considered one of the most important steps in the evolution of larger and more complex forms for it provides plenty of space for organs that can be held in place by thin membranes called mesenteries!
The Phylum Ectoprocta (also called Bryozoa) contains about 4,000 species of small colonial forms called moss animals that are found in shallow freshwater and marine environments. Although bryozoans are also well represented in the fossil record, they are also quite abundant today. Modern marine forms exploit all kinds of firm substrates including shells, rocks, marine timbers, and ship bottoms. In fact, like barnacles, the ectoprocts are one of the most important groups of fouling organisms that need to be removed periodically from ship and boat hulls. Each member of a colony lives in a tiny chamber called a zoecium (&ldquoanimal house&rdquo), which is secreted by its epidermis.
Each individual (zooid) consists of a feeding part and a case-forming part. The zoecium can be gelatinous, chitinous or calcareous, and sometimes it is impregnated with sand grains. The feeding portion of the animal contains the lophophore (a ciliated feeding device that can also be used for gas exchange), digestive tract, muscles and nervous system. Each individual lives a kind of &ldquojack-in-the-box&rdquo existence, popping up to feed and then quickly withdrawing into its protective chamber that is often sealed with a tiny trapdoor (operculum).
The Phylum Brachiopoda (&ldquoarm foots&rdquo) contains animals that are known as lampshells. This is an ancient group that is well represented in the fossil record (with some 30,000 described species) but only about 300 living species. Brachiopods resemble bivalve molluscs, but unlike bivalves, they have shells that are located on the ventral and dorsal side rather than left and right.
Brachiopods are divided into two classes based on whether they have shells that are connected by a hinge with interlocking &ldquoteeth&rdquo or with shells of unequal size. Brachiopods in the latter group are called lampshells because the larger ventral valve resembles a Roman oil lamp. Some brachiopods attach themselves to the substrate by a pedicel on the ventral valve while others just cement the ventral valve to the substrate (like an oyster) or burrow into the sediment. Like bryozoans, brachiopods also have a lophophore surrounding the mouth that is used for feeding and gas exchange.
This slide contains two specimens of the free-living turbellarian flatworm Planaria. One specimen has been stained, while the other has been injected with carbon black to reveal the extent of the blind gastrovascular cavity, which is divided into three, many-branched trunks (one anterior and two posterior). Without an anus, food must first pass through the mouth into the gastrovascular cavity where it is digested after which waste products exit through the same opening. Note the large, eversible pharynx in each planarian that is used for feeding. In the head region are lateral projections called auricles (not well developed on the specimens shown) that contain touch and chemical receptors as well as light-sensitive ocelli (eye spots).
- Buccal cavity
- Gastrovascular cavity
This slide contains a cross section through the pharyngeal (middle) region of the free-living flatworm Planaria. Note the large muscular pharynx that lies within a space called the buccal cavity. During feeding, the pharynx can be everted through the mouth and used to suck up fluids and soft tissue from captured prey. Two branches of the extensive gastrovascular cavity can also be seen. This cavity is lined with large, vacuolated cells that comprise the gastrodermis. On the outside of the flatworm is a ciliated epidermis that contains many gland cells as well as dark-staining rod-shaped bodies called rhabdites that can discharge their contents to form a protective mucous layer around the body. Lacking a body cavity, the space between the gut and epidermis in these acoelomates is filled with a meshwork of mesodermal parenchyma as well as muscle fibers that run circularly, longitudinally and diagonally.
- Gastrovascular cavity
- Rhabdites on epidermis
This slide shows a stained whole mount of the Oriental liver fluke (Clonorchis sinensis), an important trematode parasite of the humans in many regions of Asia, especially China, Southeast Asia and Japan. Humans are infected by eating raw or poorly cooked fish containing the encysted metacercariae. After being ingested, these cysts dissolve in the intestine, releasing the young flukes which then migrate to the bile duct and liver.
- Mouth and oral sucker
- Intestinal cecum
- Genital pore
- Ventral sucker (acetabulum)
- Intestinal ceca
- Yolk glands
- Yolk duct
- Seminal receptacle
- Excretory bladder
This slide shows the redia larva of a trematode parasite. This larval stage normally develops in the tissues of an aquatic snail. The redia contains groups of cells called "germ balls" that eventually develop into the tailed cercaria larvae, which emerge from the snail and penetrate a second intermediate host or encyst on vegetation to become a metacercaria.
This slide shows the tailed-cercaria larva of a trematode parasite. This larval stage, which normally develops in the tissue of an aquatic snail, will emerge from its intermediate host and penetrate a second intermediate host or encyst on vegetation to become a metacercaria.
This slide contains stained sections of the dog tapeworm Diplydium caninum taken from four different regions. The anterior most portion contains the scolex, a specialized attachment organ that often contains hooks and/or suckers. The rest of the body is divided into a linear series of segments called proglottids, each of which contains a complete set of reproductive organs. The youngest proglottids in the first part of the strobila (body) of the tapeworm are immature, while those in the middle are mature. The oldest terminal proglottids are gravid, which means they are filled with eggs. Dogs and cats can become infected by eating adult fleas (the intermediate hosts) containing cysticercoid larvae.
- Vas deferens
- Yolk gland
- Genital pore
This slide shows a mature proglottid from the dog tapeworm Diplydium caninum. Note that there are two complete sets of male and female reproductive structures that include testes, vasa deferentia (the plural of vas deferens), ovaries, yolk glands, vaginas and genital pores. Dogs and cats become infected by eating adult fleas (the intermediate hosts) containing cysticercoid larvae.
- Excretory canal
- Genital pore
- Vas deferens
- Yolk glands
This slide shows a mature proglottid from the tapeworm Taenia pisiformis, a species commonly found in the small intestines of dogs and cats. Note that each segment contains a complete set of reproductive structures including testes, vas deferens (sperm duct), ovary, yolk gland, vagina and genital pore.
This slide shows a scolex from the anterior most region of the tapeworm Taenia pisiformis. Note the series of hooks on a raised portion of the scolex called a rostellum as well as the four lateral suckers. These hooks and suckers enable to tapeworm to remain attached to the intestinal wall of its host.
Hooks on rostellum
This slide shows a magnified view of the raised tip of the scolex (rostellum) from the dog and cat tapeworm Taenia pisiformis. Note the formidable array of hooks that are used by the tapeworm to hang on to the intestinal tract of its host.
This slide shows the cysticercus larva of the tapeworm Taenia pisiformis. Note the invaginated scolex on the right end of this "bladder worm". After infected tissue of the intermediate host is eaten by the definitive host, the scolex everts and attaches to the lining of the intestine by means of hooks and suckers.
This slide shows a stained specimen of an adult spiny-headed worm belonging to the Phylum Acanthocephala. Although human infections have been recorded, adult worms normally parasitize the digestive tracts of fish, birds and domestic and wild mammals. The larvae of spiny-headed worms develop in various species of crustaceans or insects. Note the everted proboscis containing numerous recurved spines that give the organism its name. These spines (which permit the worms to remain attached to the digestive tract) can cause massive and sometimes painful destruction of the intestinal mucosa.
Acanthocephalan proboscis (close-up)
This slides shows two stained rotifers. These pseudocoelomate animals derive their name from a distinctive ciliated crown (corona) that, when beating, gives the impression of a rotating wheel. The movement of these cilia creates water currents that draw food items into the mouth of the organism. Once inside, food is chewed and ground up in a muscular portion of the pharynx called a mastax that is equipped with small hard jaws called trophi. Although there are a few marine species, most rotifers are found in freshwater habitats throughout the world.
Photographs of living rotifers
This microscope image shows two live specimens of the common rotifer Philodina. Note the lateral extension of the body wall in the head region of the specimen on the right (pointed to by the red arrow). This structure (which is called an antenna) contains many, tiny sensory bristles. The corona ("wheel organ") containing two large ciliated trochal discs and foot with its two toes (the spurs pointed to by the blue arrow) can be seen on the specimen on the left. Pedal glands (which open by ducts at the tips of the toes) produce an adhesive substance used for temporary attachment to the substrate.
This microscope image shows a magnified view of the freshwater rotifer Philodina. Note the conspicuous corona (wheel organ) with its cilia and the centrally-located mastax (pointed to by the red arrow), a muscular portion of the pharynx equipped with chitinous jaws (trophi) that grind and shred ingested food.
This microscope image shows another species of rotifer in the genus Monostyla. This common freshwater species has a rigid, chitin-like covering called a lorica.
This slide shows several zooids of the freshwater ectoproct Plumatella. Note the conspicuous lophophores. These feeding devices consist of masses of ciliated tentacles borne on ridges surrounding the mouth. In addition to reproducing by budding, freshwater bryozoans reproduce asexually by means of special resistant bodies called statoblasts (not visible on this slide). These dark, disc-shaped structures (which are similar to the gemmules of freshwater sponges) are produced during the summer and fall, and can remain dormant until environmental conditions improve in the spring.
This slide shows a portion of a branching colony of the marine bryozoan (ectoproct) Bugula. Branching within the colony is produced by repeated asexual budding of individuals called zooids. Note the tentacles of the lophophores (ciliated feeding devices surrounding the mouth that can also be used for gas exchange). Like many colonial cnidarians, ectoproct colonies are polymorphic, with most of the zooids functioning as feeding individuals. Defensive zooids called avicularia protect the colony against small organisms, including settling larvae and crawling tube-building polychaete worms and arthropods. Each avicularium resembles the head of a bird complete with powerful musculature and a sharp beak-like structure (rostrum) that is used to seize the appendages of trespassing organisms.
This slide shows a magnified view of an avicularium from the marine colonial bryozoan Bugula. Note the mandible, bird-like beak (which is called a rostrum) and musculature. Avicularia protect the colony from small organisms, including settling larvae and crawling tube-building polychaete worms and arthropods.
This is a slide of a monogenetic fluke taken from the gills of an Atlantic stingray. Unlike the digenetic trematodes, monogenetic species have a direct life cycle in which ciliated larvae called oncomiracidia develop on or within a single host. Although a few species are found in the urinary bladders of frogs and turtles, most such flukes cling to the gills and external surfaces of fish by means of a posterior attachment organ called an opisthaptor that is equipped with hooks.
This slide shows a stained whole mount of the sheep liver fluke (Fasciola hepatica). This large trematode is a common parasite of sheep and cattle, which become infected by eating aquatic plants containing the encysted metacercariae (juvenile flukes). Once ingested, the cyst walls are digested and the larvae burrow through the intestinal wall to the body cavity and eventually to the liver.
This slide shows an adult specimen of the lung fluke Paragonimus westermani. Found in east Asia, southwest Pacific and some parts of South America, the fluke parasitizes a number of wild carnivores, pigs, rodents and humans. Infection with lung flukes causes respiratory symptoms, with breathing difficulties and chronic cough, and fatalities are common! Humans get infected with lung flukes by eating raw or poorly-cooked freshwater crabs containing the fluke metacercariae.
This slide shows a pair of adult blood flukes in copulation. Blood flukes differ from most other flukes by being dioecious (i.e., having separate sexes). Males are larger and have a large, ventral groove called a gynecophoric canal posterior to the ventral sucker that holds the smaller (more darkly stained) female during copulation, which is continuous. Schistosoma mansoni is one of the three species of blood flukes responsible for the disease in humans called schistosomiasis. Humans get infected when the tailed cercaria larvae (which escape from freshwater snails that serve as their intermediate hosts) burrow into the exposed skin of individuals bathing, swimming or working in such habitats.
This model includes several views of a free-living turbellarian flatworm. The image on the left shows the nervous system (painted white), which consists of a pair of cerebral ganglia with two ventral nerve cords that are connected by a series of transverse nerves called commissures, giving it a ladder-like appearance. Other sensory structures include simple, light-sensitive eyes (ocelli) and chemical receptors that are concentrated in lateral projections of the head called auricles (because they look like ear lobes). Although reproduction in planarians can occur asexually through fission, all forms are monoecious with both male and female reproductive organs. Several features of the reproductive system (shown in blue and yellow) are also seen on the model on the left.
The model on the right shows the many branched gastrovascular cavity (shown in red) that exits through a single ventral opening at the end of a muscular, eversible pharynx (shown in off-white on both models as well as on the small upper planarian
model). Also seen on the model is a portion of the excretory/osmoregulatory system (shown in green) that is made up of protonephridia that collect and secrete some wastes as well as the excess water that enters freshwater forms by osmosis. Protonephridia consist of excretory tubules that are closed internally and open to the outside by a series of collecting ducts that lead to a posterior opening called a nephridiopore. The internal ends of each of these tubules terminate in so-called flame cells (one of which is shown on the small, lower model), which have tufts of cilia that flicker like the flame of a candle. The beating of these cilia pulls water through a mesh-like cup, producing a filtrate of water and small molecules.
- Cerebral ganglion
- Ventral nerve cord
- Circular muscle layer
- Longitudinal muscle layer
- Gastrovascular cavity
- Excretory system
- Ventral nerve cord
- Seminal vesicle
Flame cell close-up
This image shows a model of the Oriental liver fluke (Clonorchis sinensis), an important trematode parasite of the humans in many regions of Asia. Humans are infected by eating raw or under cooked fish containing the encysted metacercariae. After being ingested, these cysts dissolve in the intestine, releasing the young flukes which then migrate to the bile duct and liver. For close-up views of labeled structures found in different sections of the liver fluke, click on the links below.
1. Pharynx 2. Cerebral ganglia 3. Intestinal ceca 4. Seminal vesicle 5. Uterus
1. Mouth 2. Oral sucker 3. Esophagus 4. Intestinal ceca 5. Ventral sucker 6. Genital pore 7. Uterus 8. Yolk glands
1. Seminal vesicle 2. Uterus 3. Intestinal cecum 4. Seminal receptacle 5. Excretory bladder 6. Excretory pore 7. Yolk ducts 8. Mehlis' gland
1. Uterus 2. Yolk glands 3. Mehlis' gland 4. Ovary 5. Seminal receptacle 6. Testes 7. Excretory bladder 8. Intestinal cecum
The biology and social behavior of animals must be understood to promote reproduction. Species should be maintained alone, in pairs, or in groups, depending on their established social systems. For example, in mixed species groups of Artiodactyla, it is possible to establish species estrous cycles through a variety of techniques, including monitoring hormone levels in the urine and feces. Monitoring reproductive cycles may be used to determine when to introduce and remove breeding males, with males of other species rotated to coincide with the estrous periods of the females of each species. This may also reduce injuries from interaction between breeding males. At parturition, the males of some species should be removed for several weeks to prevent attacks on the postpartum females or their offspring. In colder climates, males should be introduced at a time that will allow births to occur during warm weather.
Artificial reproductive technologies such as artificial insemination, in vitro fertilization, and embryo transfer have been successfully used in diverse zoo species. These efforts have made a significant difference in some endangered species breeding programs (eg, black-footed ferret). However, success requires substantial investment of resources (financial, personnel, etc) to determine basic parameters of reproductive cycles and responses to pharmacologic manipulation.
An emerging management priority in maintenance of zoologic collections is the need for selective reproduction. Indiscriminate reproduction is unethical and carries the potential for overproduction that exceeds the capacity of the exhibit, the zoo, or other zoos to appropriately house the progeny. Overly successful breeding programs carry a risk of limiting resources that could compromise other captive propagation programs. Regional cooperative breeding programs such as Species Survival Plans should be followed. Management is aimed at ensuring genetic diversity of the species into the future. Contraceptive efforts in zoos are multifaceted and include permanent techniques (castration, vasectomy, ovariohysterectomy, tubal ligation), as well as reversible ones such as separation of the sexes, administration of birth control pills, hormonal implants, gonadotropin-releasing hormone agonists, and oral or injectable progestins. Reversible contraception can also be used to control timing of reproductive cycles. There is ongoing work with immunocontraception through administration of porcine zona pellucida vaccines. The Association of Zoos and Aquaria Wildlife Contraception Center (view website) is a good source of up-to-date information on contraception techniques.
1 thought on &ldquo Animals in Captivity: Do Zoos Actually Educate Visitors? &rdquo
Although the study may be valid in concluding that 62% children on a trip to the zoo are not more educated on animals after leaving, I do not think it gives reason to shut down zoos. What about the other 38%? Those may become educated and fascinated by animals and go on to do great things for the animal kingdom. I’m not sure that same interest occurs if they cannot see these animals in person and are stuck looking a picture of them. I think by closing zoos and taking animals out of captivity, you do a lot more harm to the future of animals than is currently occurring.
Do you love spending time with animals? Are you passionate about wildlife conservation? Are you fascinated by science?
If so, a degree in zoology might be for you. Zoology is a special branch of biology dedicated to the study of animal science and anatomy. Students in this field study topics like animal biology, behavior, adaptation, and conservation. They develop practical skills in field research and laboratory techniques, gaining hands-on experience working with animals of all kinds. They graduate with strong abilities in data collection and analysis, written and oral communication, project management, and team work.
These qualities—paired with their deep understanding of biology, ecosystems, and animal science—prepare zoology majors for a wide range of careers. Let's take a look at a few of the most common ones.
Nature of the Work
Veterinarians play a major role in the healthcare of pets and livestock, as well as zoo, sporting, and laboratory animals. Some veterinarians use their skills to protect humans against diseases carried by animals and conduct clinical research on human and animal health problems. Others work in basic research, broadening the scope of fundamental theoretical knowledge, and in applied research, developing new ways to use knowledge.
Most veterinarians perform clinical work in private practices. More than one-half of these veterinarians predominately, or exclusively, treat small animals. Small animal practitioners usually care for companion animals, such as dogs and cats, but also treat birds, reptiles, rabbits, and other animals that can be kept as pets. Some veterinarians work in mixed animal practices where they see pigs, goats, sheep, and some non-domestic animals, in addition to companion animals. Veterinarians in clinical practice diagnose animal health problems vaccinate against diseases, such as distemper and rabies medicate animals suffering from infections or illnesses treat and dress wounds set fractures perform surgery and advise owners about animal feeding, behavior, and breeding.
A small number of private practice veterinarians work exclusively with large animals, focusing mostly on horses or cows but may also care for various kinds of food animals. These veterinarians usually drive to farms or ranches to provide veterinary services for herds or individual animals. Much of this work involves preventive care to maintain the health of the food animals. These veterinarians test for and vaccinate against diseases and consult with farm or ranch owners and managers on animal production, feeding, and housing issues. They also treat and dress wounds, set fractures, and perform surgery, including Cesarean sections, on birthing animals. Veterinarians also euthanize animals, when necessary. Other veterinarians care for zoo, aquarium, or laboratory animals.
Veterinarians who treat animals use medical equipment, such as stethoscopes, surgical instruments, and diagnostic equipment, including radiographic and ultrasound equipment. Veterinarians working in research use a full range of sophisticated laboratory equipment. Veterinarians can contribute to human as well as to animal health. A number of veterinarians work with physicians and scientists as they research ways to prevent and treat various human health problems.
Veterinarians often work long hours. Those in group practices may take turns being on call for evening, night, or weekend work and solo practitioners can work extended and weekend hours, responding to emergencies or squeezing in unexpected appointments. The work setting often can be noisy.
Veterinarians in large-animal practice also spend time driving between their office and farms or ranches. They work outdoors in all kinds of weather, and may have to treat animals or perform surgery under unsanitary conditions. When working with animals that are frightened or in pain, veterinarians risk being bitten, kicked, or scratched.
Veterinarians working in nonclinical areas, such as public health and research, have working conditions similar to those of other professionals in those lines of work. In these cases, veterinarians enjoy clean, well-lit offices or laboratories and spend much of their time dealing with people rather than animals.
Encyclopedias and Dictionaries
Grzimek’s Animal Life Encyclopedia [via Gale Virtual Reference Library]
Extensive, completely revised and updated 17-volume version of the original work published in Germany in 1960. Incorporates recent developments in the animal world as noted by prominent advisors and contributors from the scientific community. Volume 1 covers Lower metazoans and lesser deuterostomes and volume 2 is on Protostomes. Volume 3 is about Insects. Volumes 4-5 are both concerning Fishes. Volume 6 pertains to Amphibians and volume 7 is about Reptiles. Volumes 8-11 are all concerning Birds. Volumes 12-16 are on Mammals and lastly, volume 17 is the cumulative index.
•Each entry by family includes taxonomic placement & brief details including thumbnail description, size, number of genera/species, habitat, conservation status, & distribution map.
•Detailed sections describe: evolution & systematics physical characteristics distribution habitat behavior feeding ecology & diet reproductive biology conservation status significance to humans and end with lengthy species accounts