Cetaceans - CS 143 Animal Cognition Lecture 2 THE CETACEANS...

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CS 143 * Animal Cognition Lecture 2: THE CETACEANS The Order of Cetaceans (Again, Latin names italicized ; Genus name capitalized, species not) - Great variety of cetaceans! Over 80 species , w/varied habitats, foods, body sizes, social systems, etc. - Cognition studied in 1, behavior in ~10, so “the cetacean mind” is a great mis-representation… - Key cognitive features that characterize the more studied species… - Highly Social, Large brains, Acoustic, Few long-dependent young, Playful, Collaborative Mammals – Warm-blooded, breathe air (so must come to surface regularly – no gills), nurse young - Completely aquatic (unlike other marine mammals like seals that sometimes come on land) - Can see vestigial hairs (whiskers) in fetus and infants of some species Development – Have only 1 offspring; Nurse for 2-5 years, depending on species - Long dependent young, some species not reach sexual maturity until 10-12 years old - Raised in school, much to learn! Brains – Largest brains on planet , although significant variation across species - Bottlenose dolphin = 1.5X vol of Human; Largest brain : 60ft Sperm Whale = 7.5X Human, 15lbs - Huge cerebellum; Expansive convoluted cortex ; Well developed social areas; Wired for sound ! - Buoyancy in aquatic environment supports gigantic body, and corresponding large brain size Evolution – From land animals (?Two-toed, hoofed predators: Artiodactyls ?), returned to sea ~ 55 MYA - Earliest forms: Archaeoceti ; Still had pelvis, hind limbs, poor acoustic sense; Developed into… - Ondontocetes : Small teeth, large brain, complex sound system type beats out large teeth, small brain type - Mysticetes: Probably branched off early from Odont’s (35MYA?), since Mysticete fetus has, then loses teeth - Mysticeti = Mysticetes , Baleen Whales , filter feeders, 11 species - Baleen , or “whale bone” = long keratinous plates with fringed edges - Hang down from upper palate (along elongated arched upper jaw) on both sides of mouth - Strain seawater, catch small crustaceans (e.g. krill, copepods), small fish, squid, etc. - Very large bodies
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This note was uploaded on 09/15/2011 for the course COGS 143 taught by Professor Johnson during the Spring '08 term at UCSD.

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Cetaceans - CS 143 Animal Cognition Lecture 2 THE CETACEANS...

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