One, two, three on OtterCam

More exciting images from OtterCam in the culvert.  Last time we saw the mother taking a cub downstream and I thought she had probably done the same with another one 20 minutes earlier. This time there are three!  And she is bringing them back upstream.

Otters are a real challenge for the trail camera.  It has three detection zones, one central and one at each edge of the field of view.  Something warmer than the background has to move in one of those zones to trigger the camera and it takes another 400ms (0.4s) or so before recording starts.  Cold wet otters in water have a very small heat signal (especially going away) and otters swim quickly when going downstream.  Luckily this time it was all recorded.

The mother went past with a cub at 20.38 and returned downstream 13 minutes later.

Another five minutes and she was back with the second one.  It might be an illusion on the video but it looks to have a short tail.

One hour 42 minutes later at 22.38 she went downstream again and six minutes later returned with a third cub.  If you listen carefully you can hear this one squeaking.

These cubs look quite small and are not yet able to follow mother around, something they normally manage from about six months of age.  I thought she was moving them downstream to a safer holt last time but she must have changed her mind and has brought them back again 10 days later.  They can't have been far from the culvert as it took only five or six minutes for her to go and come back again.

My guess is that these cubs are about four months old, which means they were born in July, after a mating in May (otter gestation is 63 days).  The cameras picked up lots of courtship behaviour in mid February so I suspect if that lead to a pregnancy it failed or the cub(s) didn't survive long.  Unlike, say, foxes and badgers, otters are non-seasonal breeders, presumably because they have a year-round food supply and they have thick waterproof coats so it doesn't matter that the water is cold.

I have four cameras in place in two locations so I hope to see the mother with three babies in tow in the next few weeks.