Tag Archives: NPR

Antelope moms – Not too close, Not too far

Hidden antelope fawn
Where’s the pronghorn antelope fawn?

Can you spot the pronghorn antelope fawn in the picture? I put the reveal photo below the fold, if you can’t find it. Newborn fawns can walk within an hour of birth and can briefly outrun a coyote in three days. But, they are susceptible to predation for several months. 40% to 80% of fawns will not survive this dangerous time. Until they are better at running, the fawns are very good at laying flat to the ground (especially with their big ears) and not moving a muscle or making a sound. The fawns can be extremely difficult to spot and someone can step right over them without noticing. The original NPR article (“Parents With Noisy Babies Shouldn’t Read This. They’ll Be Too Jealous”) highlights the fawns quietness. That hardly seems surprising, as any prey animal would have to adopt this behavior. Which is why I’ll never have a job writing viral news headlines.

What I found more interesting was a 1983 research paper discussing whether the pronghorn mother might reveal information about the location of the fawns*. She does feed them every 3 or 4 hours, but keeps her distance the rest of the time to not draw attention to their hiding place. Obviously, predators would love to have an easy meal, so they watch her very closely.

The researchers found the mother would quickly move an average of 70 m (230 ft) away after feeding. They calculated that a coyote would expend more energy than could be obtained from hunting common squirrels if they simply started at the mother’s initial location and began a random 360° search. Basically, that distance makes fawn-hunting a net loser for a coyote and it eventually will get hungry and go chase squirrels. Similarly, the mother stays away for a long enough period that the expected benefit for watching and waiting is below squirrel chasing.

However, the researchers did notice that the mothers have a slight tell – they will orient their head and body toward the fawns more often than away and will steal frequent glances at the hiding spot. The coyotes do not seem to have picked up on that bias, however.

* Bonus factoid: Pronghorn antelopes always have twins.

Continue reading Antelope moms – Not too close, Not too far

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Fox hunting in the snow

Here’s one I’ve been dying to post. How does a fox catch mice when they’re hiding under the snow? Foxes have sharp hearing, so they obviously listen for the little tunnelers. Pouncing in a random direction, though, is only successful about one out of five tries (18%). But, pouncing in a northerly direction is effective three out of four times (73%)! While the mechanism is yet to be worked out, the researchers think there must be some magnetism involved. Pretty cool.

The NPR link above has a general description, plus the cool drawings. Ed Yong originally covered this in 2011 and has the more technical description.

Jumping Fox