Perhaps one of the most famous things about bunnies is their affinity for hopping, but did you know not all rabbits can do this? A rare domesticated breed known as sauteur d'Alfort rabbits ditched jumping in favor of a rather bizarre method of locomotion that essentially sees them do a handstand. They can walk along on their front paws like this seemingly without much trouble.
The normal gait of jumping rabbits is called saltatorial locomotion, which is also seen in kangaroos, hares, and some rodents. New research published in the journal PLOS Genetics wanted to pin down why the sauteur d’Alforts didn’t exhibit saltatorial locomotion, so they bred some with regular hopping rabbits to find out. By comparing the genotypes of their offspring and reflecting on how this influenced their phenotype (handstand or jump) they were able to identify that there was one key gene mutation that decided to hop, or not to hop.
The offspring's genomes revealed that the handstand developmental defect centered around a specific mutation in the RAR related orphan receptor B (RORB). In the case of jumping buns, the RORB protein is common across their entire nervous system, but the mutation slashed the number of neurons in the spinal cord that produce RORB, culminating in the sauteur d'Alfort's topsy-turvy strut.
Previous research found that RORB also had an unusual effect on mouse locomotion, who lost their smooth, rhythmic gait when a similar mutation to that of the sauteur d’Alforts was present in their genome.
"This study provides a rare example of an abnormal gait behavior mapped to a single base change and the first description of a gene required for saltatorial locomotion," the authors concluded in a statement. "It further demonstrates the importance of the RORB protein for the normal wiring of the spinal cord, consistent with previous studies in mouse."
Sauteur d’Alforts aren’t the only surprise gymnasts of the animal kingdom. In 2015, an unmanned camera in the Happy Valley of Saguaro National Park in Arizona, captured a skunk doing a handstand in the middle of the night.
Shared by the National Parks Service, it looks funny but is actually an act of aggression used to intimidate its foes. It does this to appear larger and show off its bold markings – basically acting as the last warning before it sprays its notorious musk. Producing stinky goo is an expensive physiological undertaking, so the skunks will hold out if they can.