Fall Field Update

The temperatures are beginning to drop here in Tennessee, and that means leaves are changing colors, school is in full swing, and the Hellbenders are entering their breeding season. We have been tracking our Hellbenders for about 4 months now, and we’ve seen some exciting developments in the past few weeks as they enter their breeding season. In order to fully appreciate what we have found, it helps to know a little bit about Hellbender reproduction.

Hellbenders are unique among amphibians, as the males are actually responsible for providing parental care to their offspring as they develop within their eggs. Male Hellbenders will seek out large flat rocks with plenty of space underneath and usually only one entrance that can easily be protected. They will fiercely defend this territory from other males, in the hopes of attracting a female to come lay her eggs there. Should they be so lucky, a female will lay a long string of hundreds of eggs, and the male will fertilize them externally. (Mayasich and Phillips, 2003). This means it is the females that generally wander around and look for a mate when the fall comes around.

At our Tumbling Creek location, we have one female that seems to be on a mission – she has moved almost 2 miles upstream, crossing the state line from Tennessee into Georgia! Could this be for breeding purposes? We aren’t sure. This past week in the field we re-captured her and took skin swabs from her to analyze the microbiome on her skin and also to check for diseases. This allowed us to get a good look at her for the first time in months, and she appears very healthy! Since we had to do surgery on the Hellbenders to input the transmitters, one thing we are checking when we re-capture animals is to see how their surgery wound is healing up. In the case of this individual, her wound was hardly noticeable – which is a great sign.

At our other location, the Hiwassee River, we also had some interesting developments. One of our animals there has been MIA for the past two weeks. We couldn’t get a signal in any direction upstream or downstream from where it was last located. The receiver has a range of about 100 meters, but the stream is large and it is entirely possible that the animal moved further than that – especially considering the sustained large moves made by the female on Tumbling Creek. This week however, we re-located that animal to exactly the same rock where it was last found before it went missing! Could it have gone off to breed and then returned “home” ? Quite possibly.

Unfortunately, we tracked a different animal at the Hiwassee to an unfortunate spot – the river bank. This almost certainly means the animal was subject to predation from otters, which we have seen from time to time there. Hellbenders do not have many predators, especially as adults – given their secretive lifestyle hiding under large boulders in streams, but with breeding season in action they are more prone to move around and therefore may have caught the eye of a hungry otter. 😦

The rest of our individuals have been so far not moved too far from their normal rocks – with a few exceptions of course. We head out again this weekend for one of the last field days of the season and I expect that we will find even more animals moving from their normal locations to breed before the weather turns colder. We re-captured another one of our animals on the Hiwassee, again to swab for the skin microbiome and diseases, and luckily it too seemed to be doing great. I will report back with more updates soon!