2 What is a Primate?First, primates are members of the vertebrate class: MammaliamammalsPrimates are part of the subgroup of placental mammals
3 Three types of primates Prosimians (pre-monkeys)Monkeys (Old World and New World)Apes
4 Common 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)
5 Characteristics 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.
6 I. Limbs & Locomotion Tendency towards erect posture But, primates utilize a number of types of locomotionBipedalBrachiationKnuckle walkersFist walkersLimb jumpers, etc.
7 Hands & 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
10 II. Diet & TeethLack of dietary specialization – most primates are generalized feeders eating a wide variety of foodsTherefore, primates have a generalized dentition
11 III. Senses & BrainVision enhancedOlfaction reducedComplex brain
12 Vision 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)
14 IV. 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
15 V. 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.
16 Arboreal 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
17 Visual 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.
18 How 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.
20 Most 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.
22 Diet & 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)
31 Purposes of Taxonomic classification To show evolutionary relationshipAnimals grouped together or close by more closely relatedOrganize DiversityMake sense of differences & similarities
32 But, 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
36 LemursMadagascarMany different species (diversified in absence of competing primates)Became extinct in other areas
37 Lemurs 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
38 Lorises Similar in appearance to Lemurs Tropical habitats (Sri Lanka, India, SE Asia, Africa)Survived by adopting nocturnal habitsCompetition avoidance with monkeys
39 Lorises Slow, cautious climbing form of quadrupedalism Bushbabies active vertical climbers and leapersAlmost entirely insectivorousDiet supplemented with fruit, gum, leaves
40 L & 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
41 Tarsiers Nocturnal SE Asia Mated pair & offspring Diet: insects & small vertebrates they catch by leaping from branches
42 Tarsiers difficult to classify Prosimian traits:Small sizeGrooming clawsUnfused mandibleAnthropoid traitsLack of Rhinarium (moist nose pad)Orbits fully enclosed by bone
43 Anthropoids (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
44 Monkeys ~ 70 % of all primates are monkeys Two types: Old World or Catarrhini (downward-facing nose)New WorldCallitrichidaeCebidae
45 New World Monkeys Wide flaring noses with nostrils that face outward Almost exclusively arborealPrehensile tailsWith one exception, diurnalTwo Groups:CallitrichidaeCebidae
47 Marmosets 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
48 Cebids Larger than callitrichids 30 species Diet varies with combo of fruits & leavesMost are quadrupedalsSpider monkeys are semibrachiators
51 Still 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.
52 One family: Cercopithecidae Two subfamilies: Cercopithecines and Colobines
53 Cercopithecines More generalized than Colobines More omnivourous Cheek pouches to store food while foragingMost found in AfricaAltho, a number of macaques are found in Asia
54 Colobines Leaf diet Colobus monkey exclusive to Africa Langurs found in AsiaProbiscus in Borneo
55 Old World monkeys Variety of locomotion Guenons, macaques, langurs: arborealBaboons, patas, macaques: terrestrial quadrupedsColobus: semibrachiation and leaping
56 Significant sexual dimorphism, esp. in terrestrial quadrupeds (baboons) Females of several have genitalia that changes according to reproductive cycleEstrus– hormonally induced cycle
63 Gibbons & Siamangs Tropical SE Asia Extremely long arm limbs Curved fingersReduced thumbsPowerful shoulder musclesMost efficient brachiator
64 Gibbons & Siamangs Monogamous pairs Lack of sexual dimorphism Males share equally in child careMated pairs are very territorial
65 Orangutans Borneo & Sumatra Almost completely arboreal Solitary animalsMainly frugivorousVery large(males = 200 lbs, females = 100 lbs)
66 Gorillas Larges of living primate Knuckle walkers Exclusively vegetarianismMarked sexual dimorphismMales = 400 lbs, females 200 lbs.Family group: Silverback male & harem
67 Chimps Equatorial Africa Also knuckle walkers Large social groups with no single,dominant maleSexually dimorphic, but not as pronounced as gorillas and organutansOmniverous (even will kill for meat)
68 Chimps Large social groups of up to 50 Fluid membership Males form the core of the community, females leave, often during estrus
69 Bonobos Bonobos are another species of chimps More arboreal Have been studies especially regarding sexual relations – including female to femaleFrequent copulation and male/female bonds are core
70 It has been speculated that frequent sexual behavior serves to minimize stress between individuals