^Caro, Tim (2005). Antipredator Defenses in Birds and Mammals. University of Chicago Press. p. 250. ISBN9780226094366.
^Schwartz, Charles Walsh; Schwartz, Elizabeth Reeder (2001). The Wild Mammals of Missouri (2nd revised ed.). University of Missouri Press. p. 316. ISBN9780826213594.
^Boughman, Janette Wenrick; Wilkinson, Gerald S. (1999). "Social Influences on Foraging in Bats". Mammalian Social Learning: Comparative and Ecological Perspectives (72). University of Cambridge Press: 195.
^"Big Cat Facts". Animal Facts Encyclopedia. Copyright by Jenise Alongi. Retrieved March 17, 2016.
^Caughey, Melissa (2015). A Kid's Guide to Keeping Chickens: Best Breeds, Creating a Home, Care and Handling, Outdoor Fun, Crafts and Treats. Storey Publishing. p. 90
^Winter, Lisa. The Ultimate Guide To Chinchilla Care. Simple Sequence Books. p. 24.
^Power, Carla (September 4, 2000). "Ruins with A View". Newsweek International: 24.
^White, Gilbert (1837). The natural history and antiquities of Selborne. With The naturalist's calendar and miscellaneous observations. p. 449.
^Wilson, Ben (1998). Dolphins of the World. Voyager Press. p. 29. ISBN9780896585362.
^Harley, Heidi E. (13 November 2007). "Whistle discrimination and categorization by the Atlantic bottlenose dolphin (Tursiops truncatus): A review of the signature whistle framework and a perceptual test". Behavioural Processes. 77 (2). Elsevier: 243–268. doi:10.1016/j.beproc.2007.11.002. PMID18178338.
^Thomas, Jack Ward; Toweill, Dale (2002). Elk of North America, Ecology and Management. New York: HarperCollins. ISBN0-8117-0571-4.
^Ballard, Jack (2012). Elk: A Falcon Field Guide. Morris Book Publishing. p. 47. ISBN9780762776269. Elk vocalizations aren't reserved just for the bulls. Cows and ... Calves may respond to the cow calls with their own low bleats. When large ..
^Mathis, Christine; Morton, E. Lynn (2010). Ferrets. Barron's. p. 87. ISBN9780764143328.
^ abHeinrichs, Anna (2002). Grasshoppers. Compass Point Books. p. 4. ISBN9780756501662.
^Gunter, Veronika Alica; Newcomb, Rain (2006). Pet Science: 50 Purr-fectly Woof-worthy Activities for You & Your Pets. Lark Books. p. 21. ISBN9781579907860.
^Wilkins, Kelli A. (2007). Hermit Crabs For Dummies. Wiley Publishing. ISBN9781118068267.
^ abSymons, Mitchell (2012). The Bumper Book For The Loo: Facts and figures, stats and stories – an unputdownable treat of trivia. Random House. p. 364. ISBN9781448152711.
^Le Clerc, Georges Louis (1793). The natural history of birds, from the Fr. of the count de Buffon. p. 54.
^Birkhead, Tim (1991). The Magpies: The Ecology and Behaviour of Black-Billed and Yellow-Billed Magpies. T & AD Poyser. p. 250. ISBN9781408137772.
^"Moose". International Wildlife Encyclopedia. Marshall Cavendish. 2002. p. 1656.
^Lindsey, Susan Lyndaker; Green, Mary Neel; Bennett, Cynthia L. (1999). The Okapi: Mysterious Animal of Congo-Zaire. University of Texas Press. p. 34. ISBN9780292788329.
^Walkley, Sarah; Zapetis, Maria; Lyn, Heidi (2018). "Vocalizations of North American river otters ( Lontra canadensis ) in two human care populations". The Journal of the Acoustical Society of America. 144 (3_Supplement): 1954. Bibcode:2018ASAJ..144.1954W. doi:10.1121/1.5068543.
^Rao, S. N. (2004). Strengthen Your English. V. V. K. Subburaj. p. 26. ISBN9788172540531.
^Stallcup, Rich (1993). Birds of California: A Guide to Viewing Distinctive Varieties. American Traveler. p. 38. ISBN9781558381322.
^Sharma, S. D. (2007). A Text Book of Scientific and Technical Communication Writing for Engineers and Professionals (3rd ed.). Sarup & Sons. p. 365. ISBN9788176257510.