Mating in bighorn sheep: frequent male reproduction via a high-risk “unconventional” tactic

  title={Mating in bighorn sheep: frequent male reproduction via a high-risk “unconventional” tactic},
  author={John T Hogg and Stephen H. Forbes},
  journal={Behavioral Ecology and Sociobiology},
Abstract Rocky Mountain bighorn rams use three distinct tactics in competition for mates. Two tactics (tending and blocking) feature defense and cooperative mating over a relatively prolonged consort period (up to 3 days). In the coursing tactic, subordinate rams fight dominants for temporary copulatory access (lasting seconds) to defended ewes. By combining population-wide genetic (microsatellite) exclusion of paternity, behavioral data and a model of bighorn reproductive competition, we… 
Age-dependent sexual selection in bighorn rams
The results indicate that young or small rams possibly achieve mating success through alternative mating tactics that are less dependent on body and weapon size, such as coursing and blocking, and sexual selection is likely to have age–dependent effects on traits such as agility, body and horn size.
Mating tactics and mate choice in relation to age and social rank in male mountain goats
Investigating how age and social rank of male mountain goats affected the formation of consort pairs with females (“tending” tactic) in a marked population at Caw Ridge, Alberta, Canada provided evidences of mate choice by males for experienced females in an ungulate and the first quantitative information on the rut of mountain goats.
Male mating effort in a polygynous ungulate
Mating effort during the rut was unrelated to ram overwinter survival, but longevity was positively correlated with mating effort between 2 and 5 years of age, suggesting that in natural populations a few high quality males enjoy both high mating success and high survival.
Mismatch between calf paternity and observed copulations between male and female reindeer: Multiple mating in a polygynous ungulate?
The frequency and possible explanations for multiple mating in reindeer are assessed using a genetic approach to determine the success of observed copulations in a semi-domesticated herd in Kaamanen, Finland, and there is no evidence that multiple mating resulted from sexual harassment by sub-dominant males, suggesting that it is likely a deliberate strategy among females.
Mating tactics of male feral goats (Capra hircus): risks and benefits
It is found that the risks of butts during coursing were high, while the evidence suggests that the EMS was probably low, Nevertheless, the existence of an effective AMT in male feral goats may have an important influence on the intensity of sexual selection and the effective population size.
Male reproductive pattern in a polygynous ungulate with a slow life-history: the role of age, social status and alternative mating tactics
The theory that survival prospects of males modulate the investments into reproduction via alternative mating tactics early in life is supported, and male Alpine ibex results indicate that their life-history strategy targets for long life, slow and prolonged growth and late reproduction.
Male reproductive success in a promiscuous mammal: behavioural estimates compared with genetic paternity
A comparison of behavioural and genetic measures of male reproductive success in a mammalian mating system in which both sexes are highly promiscuous suggests that mating tactics differ between age groups, and that alternative mating strategies among adults that do not involve forming consorts with many females also confer mating success.
Alternative mating tactics in the New Zealand fur seal (Arctocephalus forsteri): when non-territorial males are successful too
This study highlights that holding a territory is not a necessary condition for reproductive success in all otariids, predicting that competition for females is likely to cause a diversification of male mating tactics and that non-territorial tactics can yield reproductive success.
No discernable effects of trophy hunting on survivorship of ewes, ewe fecundity, or recruitment of young are found in hunted and unhunted populations of Dall sheep, Rocky Mountain bighorns, and desert bighorn sheep.
Reproductive effort and success of males in scramble‐competition polygyny: Evidence for trade‐offs between foraging and mate search
White-tailed deer practise scramble-competition polygyny where solitary males search for and assess receptivity of females scattered across the landscape, and the repeated location of potential mates and assessment of their oestrous status appear to be important constituents of male mating strategies.


Mating in bighorn sheep: multiple creative male strategies.
  • J. Hogg
  • Biology, Medicine
  • 1984
Rocky Mountain bighorn rams obtained copulations by defending single estrous ewes (tending), fighting tending rams for temporary access to defended ewes (coursing), or moving and holding ewes away
Paternal investment inversely related to degree of extra-pair paternity in the reed bunting
An exceptionally high proportion of extra-pair paternity is found in a wild population of reed buntings using single-locus DNA fingerprinting and it is proposed that males can assess their likelihood of paternity and adjust their nestling provisioning rates accordingly.
Evidence for Mate Fidelity in the Gray Seal
Genetic analysis of pups born on the island of North Rona, Scotland, reveals large numbers of full siblings, although dominant males father disproportionately few of these.
Male Dimorphism as a Consequence of Sexual Selection
A number of insect species and red deer possess two forms of males differing from each other in the extent of development of devices involved in competition for females, which is a possible mechanism for the maintenance of a genetic polymorphism.
Sperm competition games: sneaks and extra-pair copulations
  • G. Parker
  • Biology
    Proceedings of the Royal Society of London. Series B: Biological Sciences
  • 1990
Ejaculation strategies for cases when an opportunist male ‘steals’ a mating with the female of a paired male are examined, an evolutionary game of competitive ejaculation in which two (or more) males mate with the same female.
Reproductive and genetic consequences of founding isolated lion populations
In an examination of three distinct lion populations, a direct correlation was observed between genetic variability and two physiological traits, incidence of abnormal sperm and circulating testosterone, a critical hormone for spermatogenesis.
Pronghorn females choose vigorous mates
At the National Bison Range (western Montana, U.S.A.) mate choice by female pronghorn, Antilocapra americana, is clearly observable, and the behaviour of females is a likely case of mate selection by a good genes criterion.
Intraspecific Variations in Mating Strategy
Variability in behavior is examined in broad taxonomic scope with particular reference to mating strategies. The variety of strategy sets exhibited by a wide range of species is reviewed briefly and
Age-Specific Reproduction of Bighorn Ewes in Alberta, Canada
The question of whether age affects the probability of producing a lamb, lambing date, and lamb survival to autumn of bighorn ewes is addressed.