Lifespans of male tarantulas can be short. In captivity, males typically live six months to a year after their ultimate molt, the final molt in which they emerge looking noticeably different from the females of their species, possess bulbs at the end of their pedipalps which will be used to transfer sperm from his sperm web to a female, and have tibial hooks on the underside of the tibiae of his much elongated front legs. These hooks prevent the females from plunging their fangs into the males during mating.
His behaviors become focused on sperm web building and finding a mate. He is now a long-legged, migrating machine. He focuses his energy on reproduction and slowly burns out. Eating becomes secondary.
The authors of “The Tarantula Keeper’s Guide” mention knowing of a few cases in which male tarantulas had undergone a subsequent molt, referred to as a postultimate molt. In most cases, males die during this rare molt due to issues in extricating their bulbous pedipalps from the former exoskeleton. The authors also state that between them, they have had three males successfully complete a postultimate molt. In two cases the males lost their pedipalps and associated bulbs during the molt. In the third case, humans intervened, cooling the male to immobilize him, and removed the exoskeleton manually.
I certainly did not expect to return from the 2013 Invertebrates in Education and Conservation Conference to find my first adult male tarantula in his enclosure next to an exoskeleton. He successfully molted and emerged fully intact from his postultimate molt during my six-day absence. Like those few males that survive this molt, his legs are elongate and spindly. He is much weaker, and I question whether he will be able to catch prey.
Being able to observe something like this in my first mature male is certainly a rare opportunity, though I really hate to see what has become of this once vigorous, healthy, extraordinarily tractable big spider.
It’s clear his lifespan is now even more limited. I have become attached to him. He was the first spider I observed complete an entire molt, my best feeder, best demonstration spider, and the best arthropod ambassador I’ve had thus far. I hope his demise at this point is relatively easy and rapid. I’ll miss him.