Order Carnivora ≥11 families, >287 species Naturally distributed on all continents (except possibly Australia) Morphologically & behaviorally diverse Economically.

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):

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 archOther 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.)

Glenoid/ mandibular fossa

C-shaped: strong hinge,minimizes lateral movementand facilitates up & downmovement

(e.g., mustelids)

Omnivores (e.g., bears,procyonids) have more “open”glenoid fossa, permitting lateral movement

Postcranial modifications:

•loss or reduction of clavicles(increases stride length)

•fusion of carpal bones (may add support for cursorial locomotion)

Fusion of centrale, scaphoid, & lunar bonesof wrist

Carnivora

Most non-carnivorans

Non-cursorial taxa(e.g., ursids, procyonids)

Cursorial taxa(e.g., canids, felids)

Increases stride length

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

Creodonts†

Feliformia(‘cat-like’)

Caniformia(‘dog-like’)

Creodonts---Fossil carnivorans, late Cretaceous-Miocene

Outcompeted by more “modern” carnivorans?

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

Felids: “The ultimate killing machines”

Most specialized hunters of the carnivorans, relying almost exclusively on prey that they have killed themselves.

short rostrum=increasedbite force at canines

Panthera Felis& others

“Big” vs “small” cats

terminal phalanx, supporting claw

edge of fleshy sheatharound claw

horny claw

elastic ligament holdsclaw in (retracted)pads

tendon of extensor muscle

middle phalanx

Retractile (=retractable) claws? PROTRACTILE!

tendon of flexor muscle

tendon at wristholding ligaments in place

ligaments of extensor muscle

terminal phalanx

claw

4 genera, 4 sp.Africa, SW Asia

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

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

(Herpestidae)

(Herpestidae)

(Viverridae)

(Viverridae)

(Viverridae)

14 genera, 34 sp.All continents ‘cept Antarctica

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

25 genera, 65 sp.Worldwide ‘ceptAustralia, Madagascar

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

“Hypercarnivory”---too much of agood thing?

Stenotopic: restricted range of habitats or ecological conditions

Eurytopic: wide range of habitatsor ecological conditions

Hypocarnivory

Mesocarnivory

•reduced molars & non-carnassial P’s (=reduced grinding)•enlarged carnassials & canines•short rostrum•meat-only diet

•unreduced or enlarged molars•reduced carnassials•long rostrum•omnivorous diet

Hypercarnivory

masseter muscle relaxes more, allowingwide open gape

Smilodon (extinctsabre-tooth cat)

Modern felid

SmilodonThylacosmilus(extinct S. Americanhypercarnivorous marsupial)

•Hypercarnivory has evolved several times (and in severalorders)

•Usually correlated with LARGE BODY SIZE...

Cope’s Rule: Evolutionary trend towardslarger 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)

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?

Prey size (cont.)

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

Hesperocyoninae†

Borophaginae†

Cope’s Rule

1st appearance ofhypercarnivoroushesperocyonines

1st appearance ofhypercarnivorousborophagines

Millions of years ago

“Constraint” Any factor that tends to slow the rate ofadaptive evolution.

Reversal to more generalized morphology rare inhighly specialized taxa.

Hypercarnivory may lead to “adaptive peak” that can’tbe descended...