give birth to underdeveloped young who stay in mothers pouch on abdomen

give birth to more developed young after longer gestation period (bears, dogs, whales, dolphins, cows, pigs, rats, squirrels, shrews, moles, monkeys, apes

·         Found in mostly tropical areas, c and s America, sub-Saharan Africa, Saudi Arabia, Madagascar, tropical asia, japan

complexes of primate characteristics

there are 4 complexes

grasping hands

·         Pentadactyly (having five fingers or twos on each hand or foot)

·         Opposable thumb

·         Nails (not claws)

·         Sensitive tactile pads (tip of each finger)

·         Power grip: squeeze an object strongly between the pads of the fingers and the palm, allows full strength of the forearm muscles to be applied

·         Precision grip: use just the tips of your finger for fine control (Used for things like grooming social partner)

complexes of primate characteristics

there are 4 complexes

visual systems

·         Forward facing eyes

·         Stereoscopic vision, depth perception (important to know distance from one branch to another if having to swing. Also, it has been said it could have developed from flying insect predation.

·         All primates see in colours.

o   Dichromatic: blue and green

o   Trichromatic: red, blue and green (humans)

·         Greater reliance on vision, elaborate visual centers of the brain

·         Reduced reliance on olfaction (sense of smell)

·         Reduction of the snout

·         Reduction of the olfactory centers of the brain (smell)

complexes of primate characteristics

there are 4 complexes

large complex brains

·         Large brains relative to body size

·         Primates 2x larger than other mammals, humans 7-8x larger

·         In order to survive learning is important. You can learn by yourself or in social context. Learning to live in a social group.

·         Greater reliance on learning linked to reduction in reliance upon instinct

complexes of primate characteristics

there are 4 complexes

skeletal and dental features

·         Generalized limb structure

·         Generalized, flexible morphology

·         Non-specialized physical form.

·         Retention of clavicle or collar bone (charactheristic of primates that makes shoulder bone very flexible

·         Mobile shoulder joint – greater range of motion,

organisms that have fewer offspring but allow them to invest more effort into rearing them.

it usually means they live longer

·         Typically give birth to a single young (not litters)

·         Infants are relatively altricial (vs. precocial) (horse)

·         Cling to mother, not left in nests (usually) have grapsing hands (even humans) learning…

·         Longer juvenescence (post weaning juvenile development period) (many animals don’t have this, or it is very short)

dental formulas

primitive primates (most NWM and Prosimians)

later primates (OWM, apes, and humans)

2.1.3.3

2.1.2.3

·         All primates have at least a postorbital bar

·         Higher primates (haplorhines) have postorbital closure

·         Non-primate mammals generally only have postorbital process

Most primates can stand or sit with a straight back at least while resting and feeding not necessarily while moving

o   elongated third digit with claw

o   enlarged ears

o   no postorbital closure (only postorbital bar)

o   bicomate uterus (for litters)

o   several pairs of nipples

o   so have retained primitive traits, traits that came from earlier forms of primates, from general mammalian heritage

life in the trees

 proposed by elliot-smith (1920)

·         most early mammals were arboreal, but primates stayed in the trees

·         complex 3d environment with high risks

·         grasping hands, orbital convergence leading to stereoscopic vision are assets

·         problem: other arboreal mammals – lacking primate traits – are just as well adapted to life in the trees

·         also, early primates did not have orbital convergence

developed by cartmill in the 60s and 70s

­   primate pattern represents an adaptation to foraging for insects in the terminal branches of trees.

­   Based on comparative method

This theory puts forth the notion that orbital convergence, grasping hands and feet, and reduced claws were an adaptation for the nocturnal foraging for fruit and insects on terminal branches in the shrub layer of the forest. Orbital convergence would assist in gauging the prey's distance without having to move the head much like seen in modern day owls

·         problem: other arboreal mammals – lacking primate traits – are just as well adapted to life in the trees

·         also, early primates did not have orbital convergence

few living primates are visual predators(ate other things), earliest primates lacked stereoscopic vision

both eyes looking at a single object at the same time.

this gives much greater depth perception, to allow one to judge distances much better.

important trait for primates living in trees.

fruits and flower offered new primate niches

primates would have a role of pollinators and seed dispersers

frugivores (fruit)

folivores (leafs)

insectivores (social and solitary)

faunivores (meat-eaters, vertebrae, insects, other prey)

gumnivores (sap and gums)

gramnivores (seeds and nuts)

most primates have a mixed diet of several things.

diurnal:active in the day time

Nocturnal: active at night time

Cathemeral: active both day and night at random times

solitary

pair-bond

single female/multi male

single male/multi female

multi female/multi male

cohesive or fluid

name primates in the prosimii suborder

(renamed strepsirhini)

name primates in the anthropoidea suborder

(renamed haplorhini)

they retain more ancesteral traits

found in africa and asia, not in south america

large eyes

most are nocturnal

independently mobile ears

immobile upper lip

inexpressive face

rely on scent marking

moist noses

tapetum lucidum (reflects light back at night, like a dog or cat)

dental comb

grooming claw on 2nd digit

main locomotion of a prosimian

vertical clinging, or leaping (VCL)

Some can walk bipedially for brief periods

·         only found on Madagascar and neighbouring comoros islands

·         5 families – all endemic

o   Lemuridae, indriidae, lepilemuridae, cheirogaleidae, daubentoniidae

·         some of the smallest primates (used to have the biggest, but extinct)

prosimian characteristics (lemur, lorises, tarsiers)

sexual dichromatism (sexs have different colours)

not usually sexually dimorphic

lower than normal basal metabolic rate

highly seasonal breeding (once a year)

females experience extreme stress when reproductive

many species, females can outrank males. they have feeding priority and lead group movements

·         Vertical clinging and leaping (galagidae)

·         Slow climbing and walking (lorisidae)

·         All are nocturnal (they avoid competition with sympatric monkeys and apes)

·         All are fairly small in body size

·         Generally solitary

·         Eat insects and or gum, some fruit

·         Like lemurs, rely heavily on scent-marking for communication (urine to mark border or trees)

·         Higher reliance on smell and hearing

·         Don’t move together for food or rest, but still have some interaction with others

Smaller, so they need more energy

found in SE Asia

carnivore or faunivore

·         Elongated tarsal bones for excellent leaping

·         Larges eyes relative to body size of any animal (nocturnal but no tapetum lucidum)

·         Usually solitary, but some may live in pairs

·         Large reproductive investment (infants one thirds of mothers size) parking of infants.

·         Only one living genus (tarsius)

·         Same genus applied to fossil from middle Eocene in china (around 45 MYA)

·         Anthropoid features: dry nose, postorbital closure, no tooth comb, no tapetum lucidum

·         Prosimian features: unfused mandibular symphisis, grooming claw (on 3^rd digit), bicornate uterus, nocturnal

·         Monkeys apes and humans

·         Platyrrhini (NW) vs Catarrhini (OW)

·         Diurnal (except owl monkeys)

o   no tapetum lucidum

o   post-orbital closure

·         reduced reliance on smell and hearing

o   flatter faces, shorter snouts

o   dry noses

·         larger more complex brains

o   longer juvenile dependency

·         platyrrhini have broad outward-facing nostrils

catarrhini: narrow, downward facing nostrils

mexico, central america, and south america

arrived from africa by rafting 35MYA

·         all have tails (several have prehensile tails)

·         all arboreal

·         smalled body size than Old World Monkeys

·         most have 2133 dental formula

·         minimal sexual dimorphism (the smaller you are, the less sexual dimorphism)

new world monkeys

·         Smallest monkeys

·         Claw-like nails (except on big toe)

·         Feed on insects and gums

·         2132 dental formula

·         Phyletic dwarfing?

­   Some behaviour features

·         can be monogogamous

·         or polyandrous

o   one breeding female, two or three breeding males

·         twins are common (unusal in primates. Co-operative breeding)

·         males care for offspring intensively

·         highly territorial

family cebidae characteristics

capuchins, owl monkey, squirrel monkey, spider monkey

·         larger body size

·         2133 dental formula

·         Some prehensile tails

·         Diverse social systems, from pair bonding to large multi-male, multi-female groups and also fission-fusion groups

member of the cebidae family

·         Only nocturnal monkey (new or old world) (some prosmimians are nocturnal but anthropoids genus aotus is the only nocturnal)

·         Small monogamous groups

·         Male care of offspring (grooming or carrying)

o   Sexually dimorphic

o   Cohesive multi-male/multi-female groups

o   Diverse diet (fruit, insects, nuts)

o   Semi-prehensile tails

o   Brainy tool users

o   “organ grinder monkey”

o   Used in assisted living

subfamily atelinae

spider monkeys, wooley monkeys, muriquis

·         

·         Spider monkeys, wooly monkeys, muriquis

·         Largest NWM

·         Prehensile tails

·         Locomotion and anatomy similar to apes (brachiation and suspensory climbing)

·         Diverse diets

o   Frugivores (spiders, woollies)

Folivores (howlers, muriquis

cius

·         Live Brazilian atlantic coast forests

·         Live in flexible, fission-fusion communities

o   Groups splits up into smaller feeding parties to avoid competition

·         Egalitarian

·         Promiscius mating

·         Sperm competition (female mates with several males. She will have several male sperm in reproductive system. There they compete for selection)

·         No physical interaction over food. Avoid each other in feeding context.

·         Polygenyandrous: individuals are promiscius

subfamily alouattinae

howler or howling monkeys

·         Widespread: mexico, central and south America

·         Highly folivorous diet

·         Energy reduction strategy (need lots of rest)

·         Advertise territiories through long-distance calling

subfamily pithecinae

sakis and uakaris

·         No sexual dimorphism

·         Monogamy and or fission-fusion

·         Seed predators (when they eat seeds they chew it and digest it.)

Flooded forests. (living in flooded forests makes them difficult to study)

·         Smallest “cebid”

·         Traditionally classed with callithrichids

o   Claw-like nails

o   Give birth to single offspring

o   2133 dental formula

o   Maybe independently dwarfed lineage

playyrrhini (NWM)

name the monkeys

marmosets

tamarins

capuchin

owl monkey

spider monkey

squirrel monkey

wooley monkey

muriquis

howler or howling monkeys

sakis

uakaris

goeldis monkey

titi

night monkey

catarhine classification

how many subdivisions and what are they

nostrils

what is the dental formula

two subdivisions, OWM, and apes

downward facing narrow nostrils

2123 dental formula (loss of a premoldar)

superfamily cercopithecoida

Old World Monkey common characteristics

·         Found in wide variety of environments (tropical asia, sub-saharan Africa, north Africa, Arabian peninsula)

·         All diurnal

·         All single births

·         Some species are terrestrial

·         Large body size, often sexually dimorphic

­   Cercopithecinae

·         Wide range of habitats

o   Savanna, woodlands, rain forests, deserts, cities

·         Highly variable diet

o   Fruits, grasses, roots, tubers, leaves, insects

·         Highly variable social systems

o   Many multi-male/multi-female groups

·         Many sexually dimorphic

·         More terrestrial species than in any other primate group

colobinae

·         “odd nosed monkeys”

·         Colobus monkeys in Africa

·         Langurs and leaf monkeys in asia

·         All arboreal

·         Specialized folivores

o   Sacculated stomach, supports bacteria for digestion of cellulose

o   High shearing crests on teeth

·         Usually no female dominance hierarchy

·         Tannen: molecules that bind with proteins in stomach, which makes it difficult to break things down.

·         Found in Africa

·         Include the genura : cercopithecus, allenopithecus, chlorocebus, miopithecus, erythrocebus

·         Mostly arboreal (vervets, patas monkeys terrestrial)

·         Marked colour variation

·         Multi-male and single male groups

·         Female bonded

·         Adaptive radiation

·         Found in Africa

·         Some terrestrial species

·         Form mixed species groups with Guenons

·         Live in tropical rainforests usually

·         Seem to benefit from others presence.

­   Baboons: papio, mandrillus, theropithecus

·         Africa, Arabian peninsula

·         Terrestrial

·         Papio: baboon

·         Mandrillus: mandrill and drill

·         Theropithecus: gelada baboon

·         All relatively poor habitat

·         Omnivorous diet

·         Sexually dimorphic

·         Multi-level societies

·         Stable dominance hierarchy between females, more dynamic between males.

·         Male is twice the size as female

·         Females in groups are generally related

     baboon

macaques characteristics

cercopithecinae

·         Generalized diet

·         Highly adaptable (can live in forests, cities, and hot springs)

·         Imo the potatoe washer “proto culture” spread through social learning

o   Macaques started copying behaviour of potatoe washing made by one individual.

o   Helped humans ask, what is culture? We might not be the only species with culture?

·         Stable dominance hierarchy between females

·         Multi male, multi female groups

·         Female bonded;extended matrilineages

­   Ssubfamily colobinae

·         “odd nosed monkeys”

·         Colobus monkeys in Africa

·         Langurs and leaf monkeys in asia

·         All arboreal

·         Specialized folivores

o   Sacculated stomach, supports bacteria for digestion of cellulose

o   High shearing crests on teeth

·         Usually no female dominance hierarchy

·         Tannen: molecules that bind with proteins in stomach, which makes it difficult to break things down.

·         Hrdy: adaptive strategy for males

·         After group takeovers, males kill dependent offspring

·         Females return to estrus allowing infanticidal male to reproduce more quickly (before they are ousted)

·         Infanticide is costly to females (expect false estrus, female coalitions etc.)

·         Observations have been made in a large number of primate species, in the wild and in provisioned populations

·         Use a lot of habitats that are not forested. Often living close by humans

Males only kill infants they are not related to

·         No tails

·         Larger size and weight

·         Larger brain to body weight ratio

·         More upright posture

·         Longer gestation and maturation (around 9 months)

·         Lesser apes: gibbons

Great apes: gorilla, orangatang, chimp, and humans

·         No apes in the Americas

·         Usually tropical rainland habitat

·         Orangatang is the only Asian ape

Family hylobatidae: “lesser apes”

·         Gibbons and siamangs

·         Southeast asia

·         Pair bonded social system, monogamous mating system (codominant, sexually monomorphic( same size and appearance))

·         Frugivores

·         Highly territorial

·         Bracciation locomotion

·         Long, strong arms

·         Elongated hook like fingers

·         Reduced thumbs

·         Short lind limbs

·         Erect, inflexible spine

·         Rapid locomotion, allows to travel fast

­   Ffamily pongidae “great apes”

·         Genus pongo: Orangutans (only diarnul primate ranging individually or solitary)

·         Genus gorilla: gorillas

·         Genus pan: chimpanzee and bonobos

·         Advanced congnitive abilities (tool making and use)

·         Diverse diets and social systems, although all around the notion that in context of food competition. females tend to range by themselves in relation to other females

·         2 species of chimps

·                  South east asia (borneo and Sumatra)

·                  Solitary

o   Loose relationships between males and females

o   Single male territory overlaps several female territories.

·         Frugivouris diet

·         Quadrumanous climbers and palm walkers

·         Use tools in the wild (leaf gloves for spiny fruits, stick to fish for honey)

·         All apes build nests, and they build a new one everyday.

Males 2x larger than females

·         Sexual dimorphism

o   Prominent sagittal and nuchal crests on males

o   Males twice the size of females.

·         Females not bonded; transfer to new group at sexual maturity and possibly later in life as well.

·         Male silverbacks mostly intolerant of other males

·         Chest beat tells males not to come close, and is to impress females.

·         Currently 3 sub species (see distribution slide)

·         Mountain gorilla

o   Folivorous

o   Uni-male groups, but 40% with additional adult male

o   Cohesive

o   Smaller ranges

o   Males engage in displays during inter-group encounters. Extensive overlap in home ranges.

o   THV

·         Lowland

o   Opportunistic frugivore

o   Uni-male but “male network”

o   Less cohesive

o   Larger range and much longer daily travel

o   Extensive overlap in home ranges among groups – and tolerant; particularly when they use bais (vast clearing in a march area, trees cannot grow)

·         Omnivorous but focus on frugivory (meat, insects, fruit, do not like leaves but will eat them. They will hunt for antelope or red colobus. Most hunting done by males)

·         Diverse habitats (dense forests, mixed woodlands, savannas)

·         Knuckle-walkers (like gorillas)

·         Large communities (100+)

·         Fission-fusion, male-bonded, female transfer

·         Use tools, cooperatively hunt (colobus monkeys)

·         Communal defense of homerange by males

·         Culture variation (tool culture, vocalizations) (some chimps don’t use tools the same way)

·         Sometimes male will kill another male in defense of homerange even if the other male is submissive.

·         Distribution (see genus pan distribution slide)

o   Chimps north of river

o   Bonobos south of river

·         Chimpanzee

o   Feed on fruits, insects, seeds, and leaves

o   Female dispersal, NFB

o   Male residence, malebonded dominance relationships important

o   Aggressive IGE, males involved, can be lethal

o   Somestimes use leaves for medicinal purposes (leaves cleanse insides)

·         Bonobos

o   Feed on fruit in large trees, also more THV

o   Female dispersal, although females-female affiliation more frequent.

o   Within group, males have more egalitarian relationships

o   Mediate many social behaviours with sexual behaviour

Aggressive IGE, males involved fewer than chimps. Not as lethal

·         = interactions between organsims and their environment (both physical and biological)

BMR= 70*w^0.75

large bodied species use less energy per unit of weight

but need more in absolute terms

around 1kg

boundary that seperates insectivorous species, from folivourious

females compete for?

males compete for?

food

females

·         During scarcity, can switch to lower quality diet (unripe fruit, mature leaves) and or reduce energy expenditures. (scarcity is usually the wet periods for primates. The flowers are food produce in dryer season.

figs

deterrence

detection

dilution

·         Predation protection

o   The 3 d’s (detection, deterrence, dilution)

·         Acess to mates

·         Intergroup feeding competition (can defend resources that they have)

Small groups and solitary animals

o   Predation risk high, within-group food competition low

·         Large groups

o   Predation risk lower, within group food competition is higher – may lead to fission (size cannot keep growing). In some cases where food is defensible, large group may defend food resources against other groups?

·         Contest

o   Direct confrontations over resources

o   Occurs when food is clumped or patchy, higher quality

o   Can exclude others from an individual patch

o   Dominance effect on feeding efficiency

Contest competition is a form of competition where there is a winner and a loser and where resources can be completely attained or not at all. Contest competition sets up a situation where “each successful competitor obtains all resources it requires for survival or reproduction”.^[2] In contest competition resources are stable, involves competition with food and mates, oftentimes contests can be for a ritual objective such as territory or status, and losers may return to the competition another day to gain increased benefits 

·         Scramble

o   Indirect competition – getting to food items first, not worth fighting over any one patch

o   Group size effect on feeding efficiency

Occurs when food is dispersed, evenly distributed.

In scramble competition resources are limited, and the lack of necessary amount of resources per individual can and often does lead to group member starvation^[5] Contest competition is often the result of aggressive social domains, including hierarchies or social chains.^[6] Conversely, scramble competition is what occurs by accident when naturally competitors want the same resources.^[6] These two forms of competition can be interwoven into one another; some researchers have even noted the parallels between intraspecific behaviors of both competition and cooperation.^[6] These two processes can be evolutionarily adopted and they can also be accidental, which makes sense given the aggressive competition and collaborative cooperation aspects of social behavior in humans and animals.^[6] To date, few studies have looked at the interplay between contest and scramble competition, despite the fact that it is not as “cut and dry” to have two distinct types of solitary, unfaltering competition. In the insect social dynamic there appears to be a lack of understanding around the interface of contest competition within otherwise scramble competition systems.^[7] In fact, much research still needs to be conducted concerning the overlap of contest and scramble competition systems^[7] Contests can pop up even within a scramble competition system and, vice versa, scramble competition “may play a role in a system characterized by interference

 occurs when resources are limited and can be monopolized profiably, generating direct confrontations over acess to them (like musical chairs, when the music stops, everyone scrambles to get a seat because there arent' enough for everyone)

When contest competition prevails, you see the emergence of a dominance hierarchy

·         Dominance may be expressed in a variety of settings and for a variety of functions

o   Priorty of access (mates, food, space)

·         Usually individual based, but may involve coalitions

·         Usually, male hierarchy is distinct from female hierarchy

Dominance should convey advantages in terms of access to resources, unless there are alternative strategies (rhesus macaque females prefer novel males, baboon females, may prefer “friends” (males with whom they have strong affilative relationships outside of mating contexts

he result was the Socio-Ecological model, which includes the suggestion that predation is theultimate cause for social relationships in females. resource distribution andabundance was the main reason for females forming social relationships, not entirely food resourcesalone. females compete for a variety of resources including helpers or nest sites and this can also impact on their social structure. feeding competition is a valid second causal effect; regarding this theysuggested 4 modes of feeding competition, Within Group Scramble (WGS) and Within Group Contest(WGC); Between Group Scramble (BGS) and Between Group Contest (BGC). Dispersal egalitarianfemales have low WGC and BGC; Resident egalitarian females has low WGC but high BGC; Residentnepotistic females has high WGC and low BGC and Resident nepotistic tolerant females have highinstances of both WGC and BGC. 

Female grouping patterns based on levels of within group vs between group competition and scramble vs contest competiton

·         Will lead to variation in female dominance relations

o   Strict or “despotic” vs egalitarian

o   Based on kinship (nepotistic) or not

·         Also will influence long term residency of females in group (female philopatry or dispersed)

·         4 types of social systems (see slide)

o   Dispersing egalitarian

o   Resident egalitarian

o   Resident nepotistic

o   Resident nepotistic tolerant

Mitranelial? (dominant system inherit the rank of the mother)

·         Males limited by access to females, so they go where the females are

·         When females are grouped, males will try to monopolize access to them (contest competition)

If females are philopatric, males will disperse (avoids interbreeding

­                                                                                     Polyspecific associations

·         Different species may travel and forage together for extended periods of time (higher rate than average)

·         Permits greater predator protection without increased competition for food and or mates

Foraging benefits: mutual defense, finding food resources, scrounging (lower forest animals will benefit from the groups in the canopy, because of falling food)

­                                                 Primate social and mating systems

·         Solitary (orangs, lorises)

·         Pair bonded (monogamy) (gibbons, owl monkeys)

·         Unifemale/multi female (polyandry) (tamarins)

·         Uni male/multi female (polygyny from the males pt of view, monogamy from the females pt of view) (langurs, mountain gorillas)

·         Multi male/multi female (polyandrogenous) (vervets, macaques) (special case: fission fusion (spider monkeys, chimps

·         Group structure and mating system may not always be the same (during breeding season structure may be different, may be extra group matings)

­                                                                                         Reproductive strategies

·         Mammalian reproductive system constrains female strategies (females restrained in reproductive output(cannot produce another offspring during this time))

o   Must carry offspring to term and nurse them until they can forage independently

·         Males typically less involved in care of offspring

o   Male care usually less important for survival of offspring

o   Often better strategy to use their resources to access additional females

o   When benefits of investment outweigh costs of seeking new matings (rare or difficult to access females) males will provide more care (tamarins, titi monkeys, owl monkeys)

- proposed by darwin

- accounts for features with no obvious survival function (secondary sexual characteristics)

- favours traits that increase success in competition for mates

- examples: bright colouration of male birds, sexual dimorphism in baboons.

intrasexual selection: competition within the sex's, usually among males

intersexual selection: mate choice, usually stronger in females

- more variable reproductive success than females

- winners should have some advantage in mating oppurtunities.

- more common in groups with multiple females

-

- high parental investment

- they have lower productive potentional because they often are in estrus or raising young

they do not want to waste the limited oppurtunites that they have on lower quality males.

there are 3 types of female choice

- increase female fitness (defend quality resources)

- increase fitness of the offspring

- nonadaptive traits that make an individual more attractive (bright feathers)

selfish: benefits the actor and is costly to the participant

altruistic: benefits recipepent but costly to actor

mutualistic: benefical to both

spitful: costly to both

in groups with non random associations, altruists may disporportionaly associate with and help relatives.

- altruistic behaviour may evolve because it helps the kin, and outweighs the cost of selfish behaviour

also known as kin selection

implication is that primates must reconize kin

when a single female forms a stable pair-bond with two different males at the same time.

rare but is thought to occur in tamarins and marmosets

they are monkeys, apes, and humans

they consist of NWM, OWM, and apes

night monkey (NWM)

also known as owl monkey

in OWM there are two parallel ridges.

in apes, is the y shaped pattern

size of the animal generally determines what they eat.

describe

the smallest animals are insectivores

medium sized animals are frugivores

larger sized animals are folivores

smaller

more solitary

more arboreal

rely more on olfaction

one female is paired with two or more males. they share a territory or home range with their offspring.

marmosets and tamarins

when resources are scrambled or evenly distributed across the landscape. animals cannot effectivly monopolize when its dispersed this way, so they do not directlly compete over resources.

(like when a pinata breaks, everyone gathers candy, but nobody fights over one)

monogomus will both males and females will care for the offspring

in nonmonogomus females will care for offspring and males will compete with other males to inseminate females.

in species in which females cannot choose their mates access to females will be determined by competiton among males.

what is this known as?

this is known as intrasexual selection

it favors traits that enhance success in male-male competition

when females can choose their own partners.

what is this known as

intersexual selection

selection favors traits that are more attractive to females.

this could be secondary sexual characteristics.

large body size, horns, tusks, large canine teeth.

this makes males effective fighters within male-male competition