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Order Carnivora ≥11 families, >287 species

Order Carnivora ≥11 families, >287 species •Naturally distributed on all continents (except possibly Australia) •Morphologically & behaviorally diverse •Economically important in most countries •Ecologically important. Order Carnivora Recognition characters (most/all related to carnivory):

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Order Carnivora ≥11 families, >287 species

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  1. Order Carnivora ≥11 families, >287 species •Naturally distributed on all continents (except possibly Australia) •Morphologically & behaviorally diverse •Economically important in most countries •Ecologically important

  2. Order Carnivora Recognition characters (most/all related to carnivory): Dental features (present in MOST species): •Carnassial shear: P4/M1 (secondarily lost in some taxa) •Canines large, conical •Most have primitive # incisors (3/3) Cranial features: •Transverse glenoid fossa •Sagittal crest often prominent, well developed •Large brains, well developed zygomatic arch Other features: •Most are medium-sized •Acute senses (hearing, sight, especially smell) •Most are adept cursors---sprinting •Simple stomach (cecum reduced or absent in most sp.)

  3. Glenoid/ mandibular fossa C-shaped: strong hinge, minimizes lateral movement and facilitates up & down movement (e.g., mustelids) Omnivores (e.g., bears, procyonids) have more “open” glenoid fossa, permitting lateral movement

  4. Postcranial modifications: •loss or reduction of clavicles (increases stride length) •fusion of carpal bones (may add support for cursorial locomotion)

  5. Fusion of centrale, scaphoid, & lunar bones of wrist Carnivora Most non-carnivorans

  6. Non-cursorial taxa (e.g., ursids, procyonids) Cursorial taxa (e.g., canids, felids) Increases stride length

  7. Order Carnivora ≥11 families, >287 species Suborder Feliformia (“cat like”) Felidae (cats & their relatives) Hyaenidae (hyenas, aardwolves) Herpestidae (mongooses) Viverridae (civets, genets) Suborder Caniformia (“dog like”) Canidae (dogs & their relatives) Ursidae (bears) Mustelidae (weasels, otters, etc., skunks?) Procyonidae (raccoon, coati, kinkajou) Odobenidae (walrus) Otariidae (sea lions) Phocidae (seals) Pinnipeds

  8. Creodonts† Feliformia (‘cat-like’) Caniformia (‘dog-like’)

  9. Creodonts---Fossil carnivorans, late Cretaceous-Miocene Outcompeted by more “modern” carnivorans?

  10. 18 genera, 40 sp. All continents ‘cept Austr., Antarctica

  11. Felids: “The ultimate killing machines” Most specialized hunters of the carnivorans, relying almost exclusively on prey that they have killed themselves. short rostrum=increased bite force at canines

  12. “Big” vs “small” cats Felis & others Panthera

  13. Retractile (=retractable) claws? PROTRACTILE! terminal phalanx, supporting claw edge of fleshy sheath around claw horny claw elastic ligament holds claw in (retracted) pads tendon of extensor muscle middle phalanx tendon of flexor muscle

  14. tendon at wrist holding ligaments in place ligaments of extensor muscle terminal phalanx claw

  15. 4 genera, 4 sp. Africa, SW Asia

  16. 18 genera, 37 sp. Africa, S. & SE Asia

  17. 20 genera, 34 sp. Africa, S. & SE Asia

  18. (Herpestidae) (Herpestidae) (Viverridae) (Viverridae) (Viverridae)

  19. 14 genera, 34 sp. All continents ‘cept Antarctica

  20. 6 genera, 9 sp. N. & S. America, Eurasia

  21. 25 genera, 65 sp. Worldwide ‘cept Australia, Madagascar

  22. 6 genera, 18 sp. N. & S. America

  23. “Hypercarnivory”---too much of a good thing? Stenotopic: restricted range of habitats or ecological conditions Eurytopic: wide range of habitats or ecological conditions

  24. •reduced molars & non-carnassial P’s (=reduced grinding) •enlarged carnassials & canines •short rostrum •meat-only diet Hypercarnivory Mesocarnivory •unreduced or enlarged molars •reduced carnassials •long rostrum •omnivorous diet Hypocarnivory

  25. Smilodon (extinct sabre-tooth cat) Modern felid masseter muscle relaxes more, allowing wide open gape

  26. Smilodon Thylacosmilus (extinct S. American hypercarnivorous marsupial) •Hypercarnivory has evolved several times (and in several orders) •Usually correlated with LARGE BODY SIZE...

  27. Cope’s Rule: Evolutionary trend towards larger body size. Common among mammals. Advantages: -Avoid predators -Enhance reproductive success -Improve thermal effiency -Interspecific competition for food -Capture larger prey (prey size often increases over time)

  28. Prey size (cont.) Tradeoff between foraging effort & food acquired imposes energetic constraint. Smaller carnivores can subist on small prey (e.g., insects, rodents). Larger carnivores (> ca. 21 g)--small prey not worth the energy expended. Larger body size leads to HYPERCARNIVORY and overspecialization?

  29. Hypercarnivory in N. American canids Canidae---3 subfamilies Caninae Hesperocyoninae† (>28 sp.) Borophaginae† (>68 sp.) Diverse in Miocene; peak of 25 contemporaneous species. (compare with 7 extant canids in N.S. today) N. America endemics

  30. Cope’s Rule Hesperocyoninae† Borophaginae†

  31. 1st appearance of hypercarnivorous borophagines 1st appearance of hypercarnivorous hesperocyonines Millions of years ago

  32. “Constraint” Any factor that tends to slow the rate of adaptive evolution. Reversal to more generalized morphology rare in highly specialized taxa. Hypercarnivory may lead to “adaptive peak” that can’t be descended...

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