Fawns use 'escape plan' to evade predators

Fawns often bypass the nearest "escape cover" to seek out better habitats for shaking off predators, new research has found. Baby deer are more likely to survive if they use this selective technique rather than simply fleeing to the closest refuge. The study in the journal Animal Behaviour, followed white-tailed deer fawns in the Great Plains of the US. The fawns' behaviour was a surprise to the research team, they said. "We expected them to look for cover as soon as possible and try to take that cover… (but) they actually went to a better cover rather than the first available," says Jonathan Jenks, distinguished professor of wildlife and fisheries sciences at South Dakota State University. Fawns selecting grassland and wetland habitats to conceal themselves in were found to be more likely to evade predators such as coyotes, even if it meant them running greater distances to reach these terrains, the study said. But those choosing forest sand wheat fields were more likely to be captured. Contrary to the researchers' prediction that fawns would flee to the nearest available cover, only about 25% of the 128 fawns observed selected the nearest escape habitat - and 79% of those that did were captured by predators. Conversely, 63% of the fawns that did not choose the first available escape cover evaded capture. The thick vegetation of grasslands gives fawns a better chance of escape, and "it doesn't provide a trail for predators to follow fawns", says Prof Jenks.

"Because of the diverse nature of grasslands, the fawns can escape capture by the predators easily." He says that wetland habitats offer similar advantages, because the water and thick vegetation help conceal the fawns' scent. "If the predators are using the scent in order to capture the prey, they'd lose that ability when the animal, or fawn, enters the wetland habitat." Once they have escaped a predator, fawns tend to stay in the new habitat until they feel safe. "Both grasslands and wetlands provide sort of a psychological security for the prey," says Prof Jenks. The study also shows that the presence of female white-tailed deer during a chase influences a fawn's chance of survival. Young deer running with adult does are more likely to be involved in longer chases in which the females lead the young to more secure cover, particularly wetlands. Another way females help their young escape predators is by displaying "aggressive defensive behaviour" towards the pursuer. The team, which also included researchers from the University of Wyoming and Iowa State University, observed the fawns' behaviour during 45 coyote chases. The researchers had also previously participated in 83 human chases of fawns, concluding that young deer used similar predator evasion techniques during both coyote and human chases. "It appears that these does and the fawns are responding in the same way, no matter (what) the predator, whether it was a human, whether it was a coyote, or we suspect if it was a different predator," says Prof Jenks.