AMPHIBIAN: a cold-blooded animal with a spine. Amphibians breathe with gills when they are forming and then typically with lungs when they are adults.
BIHEMISPHERIC SLEEP: sleeping with both halves of the brain at the same time
CACKLE: the collective noun used for a group of hyenas
CATHEMERAL ANIMALS: those animals who are irregularly active both during the day and night
CONCHOLOGIST: those who study the shells of mollusks, such as shellfish and snails
CREPUSCULAR ANIMALS: those animals who are most active during the twilight hours of dawn and dusk
DIURNAL ANIMALS: those animals who are most active during the day
FLAMBOYANCE: a collective noun used for a group of flamingos
HIBERNATION: a resting state in which the body temperature drops and the metabolism slows drastically. Hibernation is a different state than sleep.
MAMMAL: a warm-blooded animal with a spine who gives birth to live young and feeds them milk
NOCTURNAL ANIMALS: those animals who are most active at night
PREDATOR: an animal that eats other animals
PREY: an animal that is eaten by other animals
POD: a collective noun used for a group of whales
REM SLEEP: a state of sleep during which the animal has rapid eye movements, an overall loss of muscle tone with occasional muscle jerks and twitches, and faster breathing. The brain activity during REM sleep is similar to that seen while the animal is awake. A human in REM sleep will usually experience vivid dreams with plots, characters, emotions, and sensory imagery.
UNIHEMISPHERIC SLEEP: sleep where one half of the brain is awake, with the opposite eye usually remaining open