How Hunting Affects Mountain Lion Social Organisation

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The majestic mountain lion — Photo: NaturesFan1226
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The relatively stable situation is as follows:

Like most wild cats the mountain lion lives alone. The only time normally when the mountain lion has contact with another cat is for mating purposes or, prolonged contact, when a female is nursing her kittens

Although there is no direct contact between mountain lions, there is contact via other methods namely visual, auditory and olfactory communication.

While breeding adult females like to remain in their home territory their whole lives, male mountain lions are not so fixed to their home ranges and tend to shift around as vacancies occur in other areas.

The home ranges of male cats overlaps with those of females. Also, the home ranges of males overlap between themselves sometimes. The overlap can be extensive or it can be slight or there may be no overlap but it does happen. The same overlap of home ranges can be said about females. When home ranges overlap there will be a core area where there is no overlap. In these core areas the range is not used by other cats of the same sex.

Within the breeding population “sex ratios” typically favour females. Residents of their area hold it until they die and/or, in the case of male mountain lions, until ousted by another male. Within any single home range, males replace males and females replace female mountain lions.

In addition to the above arrangement, there are nonbreeding young adults who may be dispersing from their mother’s range or transients or immigrants and sometimes older non-reproductive cats. These homeless cats frequently travel widely looking for a suitable place to call a home range and they may cross and recross occupied territories. I can recall a news article in which it was said that a mountain lion had travelled over many states, perhaps 1000 miles, from the West the USA into the East where there was supposed to be no mountain lions.

As for daughters, sometimes they acquire their mother’s range after her death and sometimes they establish a home range next to their mother’s or overlapping it.

Female mountain lions usually breed after they have established a home range. The number of resident females in an area is fairly stable and it can increase if prey populations increase and/or if female offspring create their own home ranges next to their mothers.

Female mountain lions retain their home ranges for several years. Males have a shorter tenure and also the ranges fluctuate more in size because neighbouring males compete for females.

The size of the home ranges of the mountain line varies as to which part of the geographic distribution they live in. The smallest ranges occur where there are the highest prey densities. In south-eastern British Columbia female ranges were around 55 km² while male ranges were 151 km². In Utah, the figures are much higher at 685 km² for females and 826 km² for males.

Impact of Sport Hunting on This Stable Situation

Sport hunting alters the picture. It keeps the social system in an unsettled state because it removes resident cats who would have stayed in an area for a long time.

In addition, the dynamics between individual mountain lions is more unsettled. A researcher, Logan and colleagues, speculated that

“Frequent removal of established resident males and the consequent vacancy of home areas may increase the activity of transient males and the amount of competition for available areas. Unaware of the social status of other lions and without the regular communication systems maintained by residents through scrapes, males may encounter other males more frequent and compete for tenure (dominance) directly through fighting.

In an area of Alberta (Sheep River area) for seven years a single male was dominant over 6 to 8 females. He was killed by hunters and ownership of his territory was subsequently contested by three males. The mountain lion that had been killed had a neighbouring cat who had also been killed by hunters which had allowed the first male to expand his territory.

New males sometimes kill kittens which is similar to what happens in the African lion population. This infanticide induces oestrus in female. With the killing of resident males there must be more new males.

There is a rapid home range turnover in areas where there is a lot of sport hunting. The transient males are able to find a home range as it is vacated by a hunted mountain lion but then they are quite possibly shot themselves.

In many parts of western United States, sport hunting of the mountain lion is a major cause of its death. Sporting accounts for 20 to 50% of the annual mortality in states such as Arizona, Colorado, Nevada, Montana and Texas.

In other places such as Alberta, Canada there are restrictions on the number of mountain lions that can be shot. Shooting mountains lions is often referred to as “harvesting” which I personally find rather unpleasant. In Alberta about 10% of the population is killed annually.

The recovery of the population of cats sport hunted depends on the number of cats shot as a percentage of the overall population and the sex of the cat. In an experiment in southern Utah 27% of the resident mountain lions were shot and five died naturally making a total of 42%. It took two years for the population to recover to its pre-harvest levels.

When sport hunters kill resident adult females it has the greatest impact upon the recovery of the population.

In Mexico 53% of resident adults and 58% of transient independent adults were shot. Recovery to pre-harvest levels took three years for the adult section of the population. The sex ratio after recovery was the same as before and immigrant mountain lions and young that were born in the area created the new population.

It seems, though, that it is not known whether hunting mortality should be added to mortality from natural causes (or if it compensates) but if it is added then “harvest mortality” populations of mountain lions could suffer losses of 40 to 60% which is the rate at which that particular population would become extinct. It seems that the authorities maintain a careful watch over harvest rates.

Source: Wild Cats of the World by Mel and Fiona Sunquist, ISBN-13: 978-0-226-77999-7

4 thoughts on “How Hunting Affects Mountain Lion Social Organisation”

  1. I’ll have to re-read this tomorrow, because what I’m getting right now is that the female is homebound and the male “catting around”. Typical.

    Reply

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