16 - Carnivora

16 - Carnivora

1. characteristics

   • INVERSE relationship between body size and litter size
   • INDUCED ovulation and delayed IMPLANTATION common
   • young usually ALTRICIAL 
   • hunting skills must be LEARNED
   • high brain-to-body mass ratio
   • Carnassial teeth for SHEARING (last upper premolar and first lower molar) (posterior because most force generated NEAR ARTICULATION of jaw and skull)
   • robust skull with STRONG facial musculature
   • large, complex TURBINALS provide area for olfactory receptors 
   • often with LARGE sagittal crest especially in males 
   • deep, sharply defined C-shaped mandibular fossa in strict carnivores 
   • strong hinge minimizes LATERAL MOVEMENT of jaw
   • mandibular fossa allows jaws to act as SCISSORS with carnassials as blades 
   • most with well-developed BACULUM 
   • PROLONGED copulation in species with induced ovulation or sperm competition
   • anal sacs with secretory scent glands for defense or communication
   • claws on ALL DIGITS (retractile in most cats and some viverrids)
   • Centrale, scaphoid, and lunar bones of wrist FUSED (support for cursorial locomotion)
   • Clavicle REDUCED or ABSENT (increased stride length and faster running) 
   • LARGE RANGE in body size (up to ~10m long and 3,600kg)
   • SEXUAL DIMORPHISM in most (most pronounced in polygynous species)
   • typically SIMPLE stomachs, undeveloped cecum 
   • meat easy to digest 
   • some diet specialists (insects, fish, fruit, omnivory, herbivory)

2. fossil history

   • earliest genus adapted for carnivory was WEASEL-SIZED Cimolestes (about 65 mya); basal to Carnivora, but NOT part of group
   • first true carnivores with carnassial pair appeared in EOCENE epoch (50mya)
   • great diversification in Carnivora soon after, matching boom in prey groups and vegetative biomes of that time 

3. economics & conservation

   • carnivores = the FIRST domesticated mammals 
   • many economically important furbearers throughout history (felids, mustelids, canids, procyonids, pinnipeds)
   • some persecuted because they prey on LIVESTOCK
   • many endangered or threatened species in group (6 extinctions, ~40 endangered, ~40 vulnerable) 
   • African wild dog, Andean cat, Asian golden cat, Baluchistan bear, black-footed cat, Ethiopian wolf, giant otter, jaguar, red wolf 

4. suborders & families

   • Feliformia
     • Families: Naniniidae, Felidae, Viverridae, Herpestidae, Eupleridae, Hyaenidae
   • Caniformia
     • Families: Canidae, Ursidae 
   • Pinnipedia
     • Families: Odobenidae, Otariidae, Phocidae 
     • Monophyletic group
     • probably evolved from a BEAR-LIKE ancestor in late OLIGOCENE or early MIOCENE in northern hemisphere 
     • highly adapted to marine lifestyle 
     • large bodied (35-3,600 kg) 
     • favorable ratio of surface area to volume 
     • body insulated with BLUBBER and fur in some 
     • pinnae SMALL or ABSENT 
     • EXTERNAL genitalia and mammary nipples withdrawn beneath body surface 
     • tail is RUDIMENTARY 
     • forelimbs flipper-like
     • only DISTAL limbs protrude from body 
     • Torpedo-shaped body 
     • Skull partially telescoped 
     • orbits LARGE 
     • manus and pes fully WEBBED
     • diving and swimming ability highly advanced 
   • Musteloidea
     • Families: Ailuridae, Mephitidae, Procyonidae, Mustelidae