Ibex fighting

Large ibex males face the highest risk of predation – but get to mate more often

News published:  21/08/2025

Snow leopards prefer fully grown male Siberian ibex, despite the fact that these animals are at least twice their size. While large body size gives the ibex males an edge in the competition for mates, it also makes them less agile in the mountainous terrain.

“Most large felids tend to select prey that’s roughly their own size or smaller. Snow leopards, however, actively select much larger prey. It’s a fascinating finding that reflects the unique environment these animals inhabit,” says Örjan Johansson, researcher at SLU and the Snow Leopard Trust.

Together with colleagues, he has studied snow leopards and their main prey, the Siberian ibex, in the Tost Mountains of Mongolia. The study revealed a strong preference among snow leopards for hunting prime-aged males – around six years and older – even though females are significantly smaller and might seem like easier targets. Male Siberian ibex can weigh up to 100 kg, while females weigh only 35–45 kg.

This is likely because the males’ large bodies and heavy horns make them less agile in steep terrain, making it harder for them to escape a snow leopard ambush. The snow leopard’s hunting strategy – striking from above in rugged terrain – means that agility trumps size when it comes to survival.

“Their size and horns make them more dominant in the competition for females but also increase their risk of being caught by snow leopards. This could be an example of a sexually selected handicap – where traits that improve mating success also come with a cost,” says Örjan Johansson.

Unlike peacocks, where females choose males with extravagant feathers that also make them more visible to predators, in ibex it is primarily male-male competition that drives the evolution of larger body size and horns. During the rut, males gather in large groups where dominance and fighting determine social status.

Snow leopards themselves differ from ibex – and from other large cats – in that males and females are similar in size.  This may be another adaptation to their mountainous habitat, a larger male would have a benefit in territorial disputes but perhaps snow leopards can’t get larger without losing the agility needed to catch their prey in the steep walls. .

In spring, however, there is a clear shift in prey selection: snow leopards increasingly hunt newborn kids and pregnant females, while their preference for large males decreases. 

“Young kids haven’t yet developed the agility and speed needed to escape. Females lose much of their agility in late pregnancy, making them easier targets,” says Örjan Johansson.

The study highlights how terrain can influence predation, which is important for understanding snow leopard ecology. It also has implications for the conservation and management of ibex, since both snow leopards and trophy hunters prefer large males.

How the study was carried out

To investigate prey selection, researchers fitted snow leopards with GPS collars. The GPS data showed when a leopard stayed in one location – a likely sign of a kill. Researchers then visited the site to examine the prey remains.

Ibex do not shed their horns; instead, the horns grow with a new segment each year, much like tree rings. The sex and age of killed individuals were determined based on horn shape, horn segments, and tooth condition.

In total, the team found 150 kill sites with ibex remains, from 22 different snow leopards. The ibex population was monitored over six years. Observations of 3,761 ibex allowed researchers to compare the availability of different age and sex categories with actual kills – and show that snow leopards actively prefer certain types of prey.

The research is part of the Snow Leopard Trust’s long-term study of snow leopards.

Vetenskaplig artikel

Snow leopard prey selection on the mountain-adapted ibex: seasonal switching between prime-aged males and new born kids. Örjan Johansson et al, Journal of Zoology

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