A Texas threadsnake (Leptotyphlopidae: Rena dulcis) I found last night in front of my house. Threadsnakes belong to a clade of snakes (Scolecophidia) characterized by a subterranean lifestyle and a diet of mostly ant and termite larvae. Curiously, this species has been collected alive from active eastern screech owl (Otus asio) nests, and in a 1987 paper, authors claim there may be a commensal relationship between the two organisms. About one fifth of 77 screech owl nests with nestlings contained live blind snakes; a striking finding given the tendency of owls to fatally injure and tear prey apart when feeding their young (Note: To find blind snakes reliably at all is already a feat!). Many blind snakes were scathed, suggesting transportation to the nest by the owls, and ~90% of all individuals were found alive.
According to the study, fly larvae comprise of the greatest abundance of insects residing in screech owl nests and are known prey of blind snakes, making the nests adequate microhabitats for blind snake survival. However, it’s unknown whether blind snakes can reproduce within the nests or how long they are able to survive. Once the nestlings fledge, with a decreasing supply of insect prey and drier conditions, snakes will die if they do not vacate the nests. But what about the owls? Predation of fly larvae by blind snakes may provide healthier living conditions by reducing parasitism and disease for nestlings. This reflects findings that owl nestlings that occupy nests with blind snakes reach maturity more quickly and have higher survival rates than those residing in nests without blind snakes. Without experimentation, none of these results can be attributed with causality, and it’s a stretch to say screech owls and blind snakes have a commensal or mutualistic relationship. But it’s fascinating to think that two organisms which seem so disparate from one another may regularly interact in field, and both parties have the potential to change the conditions in which the other lives in.
Below are a few more blind snakes I’ve encountered in the past, and be sure to check out my post two years ago about vocalizations in an Australian blind snake!
