Gerbils & Jirds, What's The Difference?
As well as the popular pet species, the Mongolian gerbil, there are approximately 90 other recognised species of Gerbils. As can be seen by their Classification, they are related to mice and rats, and are distantly related to squirrel like rodents.
Taxonomists break up these large numbers of gerbil species into three closely related groupings. In group one are the gerbil species known as Naked-sole and Southern pygmy gerbils, and these live south of the Sahara desert. Group two is known as Northern pygmy gerbils, and this group of species tends to live in the regions of North Africa and the Middle East. The third group, the Jirds tend to live around Central Asia. It should be noted though that some Jird species also live in North Africa and the Middle East, and some species of Northern pygmy gerbils that live as far north as Afghanistan. Apart from these three main groupings there are a few species that don't fit into any of the above groupings, such as Pachyuromys duprasis, or the fat-tail gerbil, the great gerbil, Rhombomys opimus, and Sekeetamys calurus or the bushy tailed jird.
The Jird group has several phenotypic differences from the other groups due to the habitat that they live in around the northern fringes of the gerbil's ranges. If you look closely at Jirds you will notice that their feet are furred, as is their ears and tails. These adaptations are due to the harsh environments that they are found in. Gerbils that live in the hotter regions have no hair on their ears, much less fur on the tail, and have fur on the feet. The amount of fur on the feet tends to depend on how sandy their habitat is. The fur acts as a buffer from the hot sand and also helps traction.
So if we have a look at our pet Mongolian gerbils we can now notice that they fit all the above criteria for Jirds. We can see this by their well-furred tail, fur on the ears and also furred feet. Scientists class the Mongolian gerbil as a Jird, and sometimes you may see in various texts that it is also known as the Clawed Jird. Several other gerbil species, which are actually Jirds, tend to have Gerbil attached to their common names, which confuses people further. Two examples of this are the Indian desert gerbil and the Midday gerbil, and both are actually Jirds.
When I very first started keeping gerbils and Jirds as a hobby, I was told to remember a very basic rule for classifying gerbils, this being that all Jirds are gerbils, but not all gerbils are Jirds!
Article by Eddie Cope
Online - Animal Diversity Web - Uni. of Michigan Museum of Zoology
NGS Journal - J. Barker