杏吧原创

THE monarch of the glen isn鈥檛 all he鈥檚 cracked up to be. Male red deer are
scared of bad weather, according to British researchers, and when a storm brews
the stags are more likely to move to sheltered grazing areas than the tougher
females.

Larissa Conradt of the University of Leeds and her colleagues at the
University of Cambridge investigated the grazing behaviour of red deer (
Cervus elaphus) on the Scottish island of Rhum in winter and spring, when
food is short.

When the weather is calm, both sexes prefer to graze the high-quality open
grasslands on the island. But when bad weather sets in, the researchers found
that males are the first to depart these areas for more sheltered sites, despite
poorer grazing there. This is the first evidence that the weather contributes to
habitat segregation of male and female deer, as well as other ungulates鈥攁n
idea dubbed the 鈥渨eather sensitivity hypothesis鈥�.

This is counter-intuitive, says Conradt. You would expect males to be less
sensitive to the weather, because their larger size should allow them to retain
heat better. But a theoretical model devised by the researchers suggests this
isn鈥檛 so. Although they have bigger mouths than the females, the stags can鈥檛 eat
enough to warm their excessive bulk and offset the chilling effects of the
weather.

鈥淭he average rate at which deer can ingest food increases with body weight
due to larger jaw size, but it doesn鈥檛 increase as quickly as the increase in
loss of body heat,鈥� says Conradt. Sheltering during stormy conditions is the
only way that males can stop themselves losing too much heat. 鈥淭he bigger you
are, the more you need shelter,鈥� she says.

鈥淭he hypothesis is sensible,鈥� says animal grazing specialist Iain Gordon of
the Macaulay Land Use Research Institute near Aberdeen. 鈥淢ales have higher
energy demands and they lose more heat.鈥�

Conradt鈥檚 findings could change the way deer and antelope are conserved and
managed. Expanding exposed foraging areas in deer parks will boost female
numbers, and hence population size, whereas adding sheltered areas should
promote stag survival for hunting or tourism.