Amplexed Gulf Coast ToadsIn evolutionary biology we always discuss animal’s basic needs and instinctual behaviors used to satisfy these needs. The Four F’s (fleeing, fighting, feeding, and well reproduction), are great drivers of some of the extreme or even awkward behaviors we sometimes see in nature. “Gotta do what you gotta do right?”

One day back in May of 2010 I was road cruising and a ton of rain had just fallen, the roads were thick with amphibians of all kinds. I drove down a dirt road on which both of the sides of the roads were flooded by ephemeral pools of water. The calls of Sheep Frogs (Hypopachus variolosus), Narrow-mouth Toads (Gastrophryne olivacea), Cane Toads (Rhinella marina), Couch’s Spadefoots (Scaphiopus couchii) and Gulf Coast Toads (Incilius nebulifer) among some were so loud the chorusing was deafening.

Shortly into my drive I found a very strange little scenario going on. Right next to the roadside ephemeral pool I noticed a pair of amplexed Gulf Coast Toads. Around the pair, like the scene out of some strange ritual, were 3-4 other male toads standing close by just watching, as if waiting for their turn. Well in fact, it turns out they probably were! They seemed to be acting out what would typically occur had they been just a few inches further in the actual water body. When a male and female amplex, satellite males sneak nearby trying to fertilize some of the eggs to pass on their own genetics. In this case they were just outside the water body.

However, what was the big deal with the deal female, how could that even work right? Well back in 2012 (Izzo et al. J. Nat. Hist. 46:47–48) observed similar behavior playing out. They termed it “functional necrophilia” in which even when the female is already dead, the male is able to massage the still viable eggs, out of her fresh body and fertilize them. Thereby, benefiting both individuals including the dead female, as her genes also get passed on along with his own.

The instinct of the fourth F, ‘reproduction,’ is a strong one. I guess one can relate, right? Nevertheless, we reported the first case of necrophilia in Incilius nebulifer in the journal Herpetological Review (2013, 44:4 pp. 655-656).

The force is strong with the four Fs! Of course since then (and prior to this publication) we’ve learned of necrophilia in lizards, snakes, other anurans, and it likely occurs in other taxa as well, and if we haven’t reported it, we’ll stumble upon it eventually. How successful the strategy is among other vertebrates is still a topic of discussion, but at least with some anurans we know it works!

As for the creepy satellite males standing by on watch, well, they’re just going to have to keep watching until the amplexed male works his magic massage!