Other vertebrates besides animals we typically adopt as pets—e.g., cats, dogs, horses–are being shown scientifically to have unsuspected capabilities. Squirrels, for example, are fast learners, particularly when it comes to learning tasks that involve the same skills needed to remember where they have stored food. A few others are described below.
Research shows that pigs are as smart as a three-year-old human being and more empathic and intelligent than species that humans routinely keep as pets (such as dogs and cats). Pigs learn new skills easily and adapt to complex environmental situations. They have excellent long-term memories, live in complex social communities where they learn from one another, and are cooperative and empathic. Despite their intelligence and sociability, sows are often kept in “gestation crates” without room to turn around or any mental stimulation, expected to bear litter after litter until they are finally slaughtered.
Sheep are another species that has been stereotyped as unintelligent; however, scientists at the University Cambridge have found that they have they relatively advanced learning capabilities, are adaptable, can map out their surroundings mentally, and also plan ahead. They also have an excellent memory for faces. Unflattering stereotypes have developed from sheep’s tendency to flock tightly together and follow blindly when frightened; however, researchers have pointed out the adaptive nature of this behavior as individual sheep are poorly equipped to defend themselves.
Prairie dogs are social animals, living in small cooperative groups, with well-developed complex linguistic skills. They can describe the physical features and location of predators to each other, as well as describe abstract shapes. Biologist Con Slobodchikoff, who decoded the language of prairie dogs, hopes to have developed a translation device for communication between humans and prairie dogs (and other animals) by 2020. In contrast to animals who move in order to avoid competition for resources, prairie dogs move when their kin disappear—in other words, they want to be in community.
Fish are sentient vertebrates; however, whether or not they feel pain is still open to debate. What has been documented is reciprocal cooperation among rabbitfish pairs, with one standing on guard for the other while they forage for food. This complex cognitive and social behavior is in sharp contrast to stereotypes of fish as cold, unsocial, and unintelligent.
 M. Bekoff, “Who Lives, Who Dies, and Why? How Speciesism Undermines Compassionate Conservation and Social Justice,” in The Politics of Species: Reshaping Our Relationships with Other Animals, ed. R. Corbey and A. Lanjouw, 15-26 (Cambridge: Cambridge University Press, 2013).
 S. Griffiths, “Is This Why Grey Squirrels Are So Common? Hidden Hazelnut Puzzle Reveals Intelligence and Adaptability of Crafty Rodents,” Daily Mail (6 July 2015).
 R. Gray, “Sheep Are Far Smarter Then Previously Thought,” The Telegraph (20 February 2011).
 K. Kendrick, A.P da Costa, A.E. Leigh, M.R. Hinton, & J.W. Peirce, “Sheep don’t forget a face,” Nature (November 2001), 414 (6860): 165–166.
 University of Maryland Center for Environmental Science, “Prairie Dogs Disperse When All Close Kin Have Disappeared,” ScienceDaily (7 March 2013).
 Forschungsverbund Berlin e.V. (FVB), “Do Fish Feel Pain? Not as Humans Do, Study Suggests,” ScienceDaily (8 August 2013),
 ARC Centre of Excellence in Coral Reef Studies, “I’ve Got Your Back: Fish Really Do Look After Their Mates,” ScienceDaily (25 September 2015).