What Is Zoology? Subfields, Methods and Research Compliance

Zoology is the scientific study of animals: their structure, development, classification, behavior, distribution and evolution, living and extinct, and the ways they interact with their environments. It is a branch of biology, and it is one of the oldest and broadest. This guide explains what zoology covers, how it divides into subfields such as ornithology and herpetology, the methods zoologists use, the societies and funders that support the field, and the research-compliance layer that applies whenever the work involves live wild animals, specimens or protected species.

What Is Zoology?

The word comes from Ancient Greek roots meaning “animal” and “study of.” In practice, zoology is the umbrella for any research whose organizing subject is animals rather than a particular technique or habitat. A zoologist might dissect the anatomy of a bat wing, record birdsong in a forest, sequence the genomes of related fish species, or model how a disease moves through a wildlife population. What unites these projects is the question: how do animals work, how are they related, and why do they live the way they do?

Zoology is often described through five overlapping themes:

• Anatomy and physiology — body structure, organ systems and how they function, from cellular processes to whole-organism performance such as locomotion, thermoregulation and sensory systems.
• Taxonomy and systematics — naming, describing and classifying species and reconstructing how they are related. See how to write a scientific name for the conventions zoologists and other biologists follow.
• Behavior — the study of what animals do and why, including foraging, mating, communication, social organization, migration and learning. The subfield is called ethology.
• Evolution and development — how animal forms and life histories arise and change over time, and how embryos build bodies. See what is evolutionary biology.
• Ecology and conservation — how animals relate to each other and to their habitats, and how populations can be protected. See what is ecology and what is conservation biology.

A Short History

Systematic study of animals is conventionally traced to Aristotle in the fourth century BC, who treated animals as living organisms worth describing and sorted them into broad groups, including animals with blood and without, which roughly anticipates the modern split between vertebrates and invertebrates. Later landmarks usually cited include Carl Linnaeus and the system of classification that still underlies biological naming, Antonie van Leeuwenhoek and early microscopy, and Charles Darwin, whose theory of evolution was published in 1859. The 1953 description of the structure of DNA by Watson and Crick opened the molecular era, which now shapes how zoologists study relatedness, development and genetics. Zoology today therefore blends natural history, laboratory biology and computation.

Major Subfields of Zoology

Zoology is commonly subdivided in two ways: by the group of animals studied, and by the biological question asked.

Subfields defined by taxonomic group

• Mammalogy — mammals, from rodents and bats to whales and primates.
• Ornithology — birds. Birds are among the most intensively monitored animals, in part because of long-running survey traditions and large volunteer observer networks.
• Herpetology — reptiles and amphibians.
• Ichthyology — fishes. It overlaps strongly with marine biology and freshwater ecology.
• Entomology — insects and, in practice, closely related arthropods. See what is entomology.
• Parasitology — parasites and their hosts, which crosses into medicine and veterinary science. See what is parasitology.

Other taxon-based specialties include malacology (mollusks), arachnology (spiders and relatives) and invertebrate zoology more generally.

Subfields defined by question or level of organization

• Comparative anatomy, histology and physiology — structure and function across species.
• Developmental biology and embryology — how a single cell becomes an animal.
• Ethology and animal cognition — behavior and its mechanisms and evolution.
• Phylogenetics and biogeography — evolutionary relationships and the geographic distribution of animals.
• Molecular zoology and genomics — genetic and genomic approaches to the questions above. See what is genetics.
• Wildlife biology and wildlife management — population assessment and management of wild animals, closely tied to conservation and applied ecology.

Zoology and Neighboring Fields

Zoology shades into many adjacent disciplines, and a given researcher’s department label often hides the overlap. Animal science is oriented toward domestic and agricultural species and their production, health and breeding, whereas zoology is oriented toward animal biology in general, with wild and non-domestic species prominent. Veterinary science focuses on animal health and disease and clinical care. Ecology and conservation biology treat animals as part of populations, communities and ecosystems. Marine biology is defined by habitat rather than taxon, so it includes zoology of marine animals along with other organisms. The practical difference is usually the question and the training, not the animal.

Research Methods in Zoology

Field surveys and observation

Much of zoology still starts outdoors. Field methods include transect and point counts, capture-mark-recapture, trapping and netting, camera traps, acoustic recording, telemetry and tracking devices, and direct behavioral observation. Good field design specifies sampling effort, detection issues and repeatability so that counts can be compared across sites and years. See systematic sampling for one of the basic sampling designs.

Specimens and museum collections

Preserved specimens in natural history museums and university collections are a core research infrastructure for zoology. A voucher specimen lets other researchers re-examine an identification, measure traits, extract tissue or DNA, and document where and when an animal was collected. Collections serve taxonomy, biogeography, studies of change over time and increasingly genomic work. For this reason, journals and funders often expect that voucher specimens or tissue samples be deposited in a recognized collection with accurate locality and date records. Moving specimens across borders brings its own rules; see shipping biological samples internationally and CITES permits.

Laboratory and physiological work

Laboratory zoology includes anatomical dissection, microscopy and imaging, histology, physiological measurement, controlled behavioral experiments and rearing studies. Some of this work uses live animals held in captivity or temporarily brought in from the field, which triggers animal-welfare oversight (see below).

Genetics, genomics and molecular tools

DNA sequencing now supports species identification, population structure, parentage and relatedness, phylogenetic reconstruction and the study of gene function in development and evolution. Environmental DNA and metabarcoding let researchers detect species from water or soil samples without handling animals. See what is genomics.

Data, statistics and modeling

Zoological data are often messy, spatial and observational. Occupancy models, population models, phylogenetic comparative methods and mixed-effects statistics are standard tools, and good practice includes documented sampling designs, shared data and reproducible analysis.

Societies and Professional Organizations

Zoology has both broad and taxon-specific societies. The Society for Integrative and Comparative Biology (SICB) is the main broad-scope example. It describes its mission as fostering research, education, public awareness and understanding of living organisms from molecules and cells to ecology and evolution. According to its published history, the society was formed in 1902 and was known as the American Society of Zoologists until it was renamed in 1996. It publishes the journal Integrative and Comparative Biology, formerly American Zoologist, along with Integrative Organismal Biology, and holds an annual meeting with awards for student presentations.

Many zoologists also belong to taxon-based societies in ornithology, herpetology, ichthyology, mammalogy and entomology, as well as societies in ecology, evolution, animal behavior and conservation. Such societies typically run meetings, publish journals and issue guidelines for field research and the use of animals in research. Check a society’s current guidelines before designing a study, because journals often require adherence to them.

Who Funds Zoological Research

In the United States, the National Science Foundation’s Directorate for Biological Sciences supports research and education that advances the understanding of all forms of life at all scales, from molecules to ecosystems and across space and time. Zoological projects, particularly in ecology, evolution, systematics and organismal biology, are usually directed to programs within that directorate; program names, divisional structure, solicitations and deadlines change, so confirm the current program on nsf.gov before writing a proposal. Federal land and wildlife agencies, state wildlife agencies, private foundations, museums and conservation organizations also fund applied and field work. Proposals involving vertebrate animals must address animal welfare; see vertebrate animals section (VAS) for the federal grant requirement.

Outside the United States, national research councils, environment and agriculture ministries and international conservation bodies play similar roles. Always read the specific solicitation: eligibility, data-sharing, specimen-deposition and permitting expectations vary.

Research Compliance for Wildlife and Field Work

Zoological research often sits at the intersection of several regulatory regimes. A single field project can need institutional animal-care approval, one or more government permits for taking or handling wildlife, landowner or land-manager permission, and sometimes import or export documents for specimens.

Institutional animal care and use oversight

In the United States, institutions that conduct animal research under federal funding or policy generally oversee it through an Institutional Animal Care and Use Committee (IACUC). Protocols for work with live animals are typically reviewed before the work begins. Where an institution applies this oversight to field studies of wild animals, the review may consider the capture, handling, marking, sampling and release methods and the humane endpoints of the work. See IACUC training, the 3Rs (replacement, reduction, refinement), the Office of Laboratory Animal Welfare (OLAW), and the attending veterinarian role. Researchers weighing which committee reviews what can read IRB vs. IACUC and IACUC vs. IBC. Whether a given study is covered depends on the species, the funding source and institutional policy, so ask your IACUC office early rather than assuming a wild-animal study is exempt.

Wildlife permits

Separately from the IACUC, taking or handling wild animals usually needs government authorization. In the United States, the U.S. Fish and Wildlife Service administers or coordinates permitting under federal laws and treaties including the Migratory Bird Treaty Act, the Endangered Species Act, the Marine Mammal Protection Act, the Bald and Golden Eagle Protection Act and the Convention on International Trade in Endangered Species (CITES). State wildlife agencies add their own scientific collecting permits, and federal land managers add research permits for parks, refuges and forests. Permit conditions often specify species, numbers, methods, dates and reporting. International projects add host-country research permits and, for specimens, export and import documentation.

Specimens, samples and data

Moving specimens or tissues across borders can require CITES documentation and compliance with transport rules for live animals and biological samples. Note also that benefit-sharing and permitting rules for genetic resources in some countries can apply to sequencing work on animal tissue; check the rules of the country of origin. For the research-administration view of these topics, see the related pages on occupational health programs for animal research personnel and AAALAC vs. IACUC.

Training and Careers

Zoologists typically start with an undergraduate degree in zoology, biology or a related field such as wildlife biology, ecology or animal biology. Research careers usually require a graduate degree: a master’s for many wildlife and management roles, and a doctorate for university and museum research positions. Employers include universities, natural history museums, zoos and aquariums, government wildlife and land-management agencies, conservation nonprofits and environmental consulting firms. Field experience, quantitative skills and familiarity with permitting and animal-care requirements are highly valued, and students often gain them through technician positions and thesis fieldwork.

Frequently Asked Questions

What is zoology in simple terms?

Zoology is the scientific study of animals, including their anatomy, physiology, behavior, classification, evolution and ecology.

What are the main branches of zoology?

Common branches are mammalogy (mammals), ornithology (birds), herpetology (reptiles and amphibians), ichthyology (fishes) and entomology (insects), along with question-based areas such as physiology, ethology, developmental biology, genetics and wildlife biology.

What is the difference between zoology and animal science?

Zoology studies animal biology broadly, with wild and non-domestic species prominent. Animal science focuses mainly on domestic and agricultural animals. See what is animal science.

What is the difference between zoology and wildlife biology?

Wildlife biology is an applied area of zoology and ecology concerned with the study and management of wild animal populations and their habitats. Zoology is the wider discipline.

What was the American Society of Zoologists?

It is the former name of the Society for Integrative and Comparative Biology (SICB). Per the society’s history, it was founded in 1902 and renamed in 1996.

Does fieldwork with wild animals need IACUC approval?

Often yes, if the institution or funder applies animal-care oversight to the study, and it will often need separate government permits as well. The requirements depend on species, location, funding and institutional policy, so consult your IACUC office and the relevant permitting agencies before starting.

Where can I learn more about related disciplines?

Start with the branches of science hub, then see biology, ecology, entomology and conservation biology.