2What is a Primate?First, primates are members of the vertebrate class: MammaliamammalsPrimates are part of the subgroup of placental mammals
3Three types of primates Prosimians (pre-monkeys)Monkeys (Old World and New World)Apes
4Common Mammal Traits Fur (or body hair in Humans) Long gestation & live birth (relative to other types of organisms)Heterodontism (different kinds of specialized teeth)Ability to maintain constant body temp (Homeothermy)Increased brain size (greater ability for learning and behavioral flexibility)
5Characteristics of Primates Difficult to define by one or two common traitsPrimates are generalized (rather than specialized) mammals.Defined by evolutionary trendsNot all traits found in every member of the order.
6I. Limbs & Locomotion Tendency towards erect posture But, primates utilize a number of types of locomotionBipedalBrachiationKnuckle walkersFist walkersLimb jumpers, etc.
7Hands & Feet Great degree of Prehensility Five digits on hands/feet (contra horses)Opposable thumbIn most- divergent & partially opposable big toeNails on all or some digitsHighly sensitive tactile pads on digit ends
12Vision All primates rely heavily on vision Color vision in Diurnal primates.Stereoscopic visionEyes in front of skull, overlapping fields of visionAccurate 3-D visionIncreased depth perceptionPoint to Ponder: Why would this be an adaptive trait? (hint: think environment)
14IV. Maturation and Learning As placental mammals, primates have relatively long gestation periodsAlso have few offspring, delayed maturation, longer lifespan than other mammalsGreater dependence on learned behavior
15V. Behaviors Tend to be diurnal Increased flexibility in behavior Tend to live in social groupsIn many primate social groups, males are permanent members – unusual among mammals.
16Arboreal Adaptation Hypothesis Traditionally, the arboreal adaptation seen as the primary factor in primate evolutionSelected for 3-D and color vision (why?).Grasping prehensile hands/feet to graspTropical arboreal environment = varied foods
17Visual Predation hypothesis Alternative to the AA hypothesisPrimates may have first evolved in bushy forest undergrowth relying on insect dietGrasping hands & vision for grabbing insects.Tree jumping came later a means of locomotion that grasping hands allowed.
18How to choose which hypothesis is correct? Not necessarily mutually exclusiveMany primate features may have been developed in non-arboreal settingsRegardless, primates are primarily tree dwellers and whatever traits their ancestors had “preadapted” them for arboreal existences.
20Most primates are arboreal, living in forest or woodland areas Some Old World primates do spend considerable time on land.No primate, except for humans, is fully terrestrial – all spend some time in trees.
22Diet & Teeth Omnivorous w/generalized dentition Although some primates prefer some food items over others, most eat a combo of fruit, leaves, and insects.Some do eat meat (chimps & baboons)Some are leaf specialists (Colobine monkey)
31Purposes of Taxonomic classification To show evolutionary relationshipAnimals grouped together or close by more closely relatedOrganize DiversityMake sense of differences & similarities
32But, system is not necessarily perfect Studies of Orang chromosomes show it much different from African apes (and these are closer to Humans than Orangs).Humans & Chimps most closely related(based on DNA studies)Some researchers use a different scheme to show closeness of Chimp/Human
36LemursMadagascarMany different species (diversified in absence of competing primates)Became extinct in other areas
37Lemurs Range in size from 5”, 2 oz. to +2’, 22 lbs Larger lemurs are diurnal, omnivorousSmaller lemurs are nocturnal, insectivoresMany forms are arboreal, others are more terrestrialSome live in large social groupsOthers (Indri) are monogamous pairs
38Lorises Similar in appearance to Lemurs Tropical habitats (Sri Lanka, India, SE Asia, Africa)Survived by adopting nocturnal habitsCompetition avoidance with monkeys
39Lorises Slow, cautious climbing form of quadrupedalism Bushbabies active vertical climbers and leapersAlmost entirely insectivorousDiet supplemented with fruit, gum, leaves
40L & L Vision is stereoscopic, but less developed than anthropoids Color vision in diurnal, but not nocturnalGrooming claw on second toe (not fully nailed)Longer life spans than similarly sized mammals
41Tarsiers Nocturnal SE Asia Mated pair & offspring Diet: insects & small vertebrates they catch by leaping from branches
42Tarsiers difficult to classify Prosimian traits:Small sizeGrooming clawsUnfused mandibleAnthropoid traitsLack of Rhinarium (moist nose pad)Orbits fully enclosed by bone
43Anthropoids (monkeys, apes, H.s) Generally larger bodyLarger brains in absolute and relative sizeIncreased reliance on visionFully forward placed eyes; bony plate back of eye socket; greater degree of color visionFused mandibles; less specialized dentitionFemale anatomy different; longer gestation; longer maturation; increased parental careMore social interaction
44Monkeys ~ 70 % of all primates are monkeys Two types: Old World or Catarrhini (downward-facing nose)New WorldCallitrichidaeCebidae
45New World Monkeys Wide flaring noses with nostrils that face outward Almost exclusively arborealPrehensile tailsWith one exception, diurnalTwo Groups:CallitrichidaeCebidae
47Marmosets and Tamarins Most primitive monkeysRetain claws instead of nails (used like squirrels to climb trees)Twins rather than single birthsFamily groupsMated pair2 males & 1 femaleMales very much involved in infant care
48Cebids Larger than callitrichids 30 species Diet varies with combo of fruits & leavesMost are quadrupedalsSpider monkeys are semibrachiators
51Still finding new monkeys April 22, 2000: Conservation International announced the discovery 2 new marmoset species in the Amazon Basin of Brazil. Both species are squirrel size. They have been named Callithrix manicorensis and Callithrix acariensis. Since 1990, ten new monkey species have been discovered in Brazil.
52One family: Cercopithecidae Two subfamilies: Cercopithecines and Colobines
53Cercopithecines More generalized than Colobines More omnivourous Cheek pouches to store food while foragingMost found in AfricaAltho, a number of macaques are found in Asia
54Colobines Leaf diet Colobus monkey exclusive to Africa Langurs found in AsiaProbiscus in Borneo
55Old World monkeys Variety of locomotion Guenons, macaques, langurs: arborealBaboons, patas, macaques: terrestrial quadrupedsColobus: semibrachiation and leaping
56Significant sexual dimorphism, esp. in terrestrial quadrupeds (baboons) Females of several have genitalia that changes according to reproductive cycleEstrus– hormonally induced cycle