Snakes have been filmed apparently learning to hunt while still in the womb.
Researchers at the Chiricahua Desert Museum in New Mexico observed fetuses of copperhead snakes moving their tails in a behavior known as “caudal attraction.”
This is a tactic used by certain species of snakes to attract prey. Tail movements are often mistaken by prey for a worm or other creature. When prey approaches the snake, it will lunge and attack.
Not all snake species use tail lures, but the copperhead, a member of the viper family, adopts the tactic soon after birth.
However, the findings, published in the journal Open Science by the Royal Society, suggest that snakes start learning this behavior even before they leave the womb.
Scientists have already observed prenatal behavior in mammals and birds, but this is the first time it has been observed in this species.
“Prenatal movements in humans and other vertebrates are known to be important for musculoskeletal and sensorimotor development,” the study wrote. “The fetal behaviors we described for copperheads, and possibly other snakes, may be equally important and influence early survival and later fitness.”
The study said that fetal behavior in reptiles is “largely understudied.”
After accidentally observing the behavior of a pregnant snake, the researchers advanced their study and used ultrasound to evaluate another 18 late-pregnant copperheads.
During the evaluation, the scientists found that 11 snake fetuses moved their tails in this way.
The study said the movements were “indistinguishable” from the caudal attraction. The behavior was caught on film, where the fetus can be seen wagging its tail inside the womb.
Using the same methods, the scientists tested this behavior in two
species of rattlesnakes, which do not attract caudal: None of the late fetuses showed any type of tail movement, according to the study.
The study said that because they only had a small sample of subjects, more research will be needed to determine whether these tail flicks occur in non-caudal decoy species.
For copperheads, however, it certainly appears that these tail flicks are “an essential developmental precursor” to hunting behavior.
Scientists believe that while the fetus is still developing, its “musculature and neuromotor systems” are preparing for “major postnatal activity.”
The tail wags occurred “randomly and spontaneously,” which the study described as “a form of fetal motor babble.”
As fetal movements in reptiles are not widely studied, these findings show one of the few insights into prenatal development in snakes.
“Although the duration of tail flicks in fetal copperheads was relatively short compared to caudal attraction in young and older snakes, this was not the case.
unexpected,” the study said.
“Fetal movements in vertebrates, in general, are shorter-lived than those exhibited after birth.”