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Searching for Animal Literature

This page provides a brief introduction to running time-limited searches for animal literature in freely available databases such as PubMed.

For more advanced animal searching resources please see the links below to our Open Science Framework site.

Search Tips


Use the acronym PICO to help define concepts that you want to include in your question. To learn more view the ASK portion of the RCVS EBVM Learning Tutorial.

  • P - problem, population, patient (population or patient may include species, breed, age, life stage, gender, or geographic location)
  • I - Intervention
  • C - Comparison, Correlation
  • O - Outcome

Boolean Operators

  • Search terms will combine with the Boolean AND by default. For example a search for dolphins porpoises whales will search for dolphins AND porpoises AND whales.
  • Combine similar terms for the same concept (synonyms) with the capitalized OR to broaden a search. For example, if you intended to search for publications about marine mammals, nest similar terms combined with OR in parentheses (dolphins OR porpoises OR whales).
  • Combine different concepts with AND, for example (dolphins OR porpoises OR whales) AND (diet OR food OR feed)

Quotation Marks

When searching for some concepts you may need to place a phrase in quotation marks. For example, a search for marine mammals without quotation marks might return results about military personnel. Instead, search for “marine mammals.


To search for variations on the ending of a term, search for the root of the term with an asterisk at the end. Use caution when truncating however, as a search for cat* will return articles about cats, catalase and COPD Assessment Tests (CATS). In PubMed, truncation also works for phrase searching, as long as the truncation symbol is at the very end of the phrase. So while you can search “marine mammal*”; searching “marine mam*al” or “marine* mammal” is incorrect. If you would like to learn about advanced wildcard or proximity searching, consult a librarian.

Controlled Vocabulary

Some databases index articles with controlled subject headings. Searching these subject headings in combination with keywords will allow you to run a more comprehensive search. MEDLINE indexed articles in PubMed have controlled subject headings assigned called Medical Subject Headings (MeSH terms) that can be viewed at the end of a PubMed abstract. A PubMed article found with a search for “marine mammals” has the MeSH term Cetacea assigned. Right click on an abstract MeSH term
to view the definition of the term and a hierarchy of broader and narrower terms.

Artificial Intelligence in Databases

Some databases will modify your search by adding terms, including controlled vocabulary, to try to optimize retrieval. PubMed refers to this as Automatic Term Mapping. You can view how PubMed is modifying your search by clicking on Advanced > scroll to History and Search Details > click on the chevron to open. Using quotation marks or truncation will turn this off.

Apply What You Learned

Now that we learned about quotation marks, controlled vocabulary, truncation, and Boolean operators, a more comprehensive search would be:

("marine mammal*" OR cetacea OR dolphin* OR whale*) AND (diet OR food OR feed)

Narrow Search with Limiters

If you are returning too many results, use limiters in the sidebar to narrow your results. In PubMed it may be tempting to use the “Other Animals” limiter. This is intended to search for animal models of human disease, and it may not be applicable to clinical veterinary medicine.

For clinical decisions limit your PubMed search to article types with higher levels of evidence (guidelines, systematic reviews, meta-analyses, and randomized controlled trials). If these article types do not show up in your list, click on “additional filters” to add them. Limiters for “Clinical Trial, Veterinary” and “Observational Study, Veterinary” were added in 2019 and will not be effective for searches prior to that year.

For more information see PubMed Online Training.

Finding Full Text Articles

It is important to stay up to date on new findings in your profession. Just as there are fees for quality continuing education conferences, there are often fees for quality publications. Due to publisher agreements institutions are prevented from providing remote library access to those unaffiliated with the institution (as current student, faculty, or staff). If you are not affiliated with an institution that provides access to subscription based content, consider the following when searching for literature:

  • Does your alumni association provide online library access privileges?
  • Does your state provide online library access privileges for licensed health care providers?
  • Did the author publish gold open access, or make a green open access copy available? Try the Open Access Button or Unpaywall.
  • Does your professional association membership provide online library access privileges?
  • Can you pay to purchase or rent articles on-demand (DeepDyve), subscribe to individual journals, or subscribe to a fee-based online veterinary library (VetMed Resource, AO VET, RCVS Library, EBSCO Veterinary Source)?
  • Does your local public academic institution provide public access from on-site library computers?
  • Does your public library provide interlibrary loan copies of articles?

Recommended Resources


Animal Journals Currently Indexed in PubMed

Facets – categories of information and associated standard terminologies/ontologies: 

Controlled Vocabularies relevant to animal searching:

Example Search Hedges - standardized strategies used for comprehensive searching on a topic. Contact for access to the search hedges.

AVIS Search Strategies Working Group Hedges 

Zotero Animal Search Working Group Library