I received a shipment of prefabricated skinned rabbit last week and the shipment seemed unusual. Rabbits have a very close resemblance to cats once their “hair” and skin have been removed. Is there a telltale sign that I’m working with Bugs Bunny, not Sylvester?
I have a suspicion that Elmer Fudd is running out of legitimate product.
All jokes aside, how do you tell the difference?
In Germany we have an old (joking) saying that roughly translates to "head off, tail off - bunny", so your question is legitimate. But first thing's first: There is no health risk1 involved if you ate the latest shipment of "meowling rabbit".
(To cat lovers everywhere: This is no endorsement, I have a much loved and pampered cat, too!)
The most obvious differences are
But I suspect these would be removed prior to sale, so we'd have to dig a bit deeper into anatomy:
Shoulder blades:
Cats' shoulder blades are rounded on top, especially in the front, making the shoulder blade almost semicircular with the ridge making for two differently shaped parts, rabbits' shoulder blades are triangular with the ridge somewhat parallel to the front side.
Femur (thigh bone):
A cat's femora are straight, whereas a rabbit's is more or less bent, especially pronounced in older animals. Same applies to a lesser extent to radius and ulna (forearm), but they might have been removed.
Ribs:
Cats' ribs are "rounder" than rabbits' ribs according to this source. I can't say by how much, but @aitchnyu's comment below suggests the difference is obvious enough to play a significant role in the novel/movie Papillon.
Pelvis:
The same source as above states that the foramen obturatum (= the loop-like opening near/below the hip joint) is oval in rabbits and round in cats. I couldn't find a good picture to show this, though.
Here's a rabbit:
Source: www.onlineveterinaryanatomy.net
And a cat:
1 other than the general risk every meat from questionable sources brings
In the textbook Text-book of meat hygiene: with special consideration to ante-mortem and post-mortem inspection of food-producing animals (Edelmann & Eichorn, 1908), pages 64-65 concern determining the difference between a cat and rabbit:
The following differences in the skeleton are especially to be mentioned: The lateral processes of the lumbar vertebrae which are directed forward terminate in the rabbit (Fig. 34) in two extensions, of which one is directed forward the other backward; in the cat they terminate in a point. The body of the first three lumbar vertebrae in the rabbit contains thorn-shaped ventral processes (Fig. 34 a). The ribs of the rabbit are flat and broad; those of the cat are rounded. On the scapula of the rabbit the acromion turns around posteriorly and terminates in a long point, which is directed backward (Fig. 37)). Radius and ulna are completely separated in the cat (Fig. 35); in the Leporides they are united (Fig. 36). On the humerus of the cat is an elongated fissure over the median condyle of the distal end (Fig. 39). The femur of the rabbit (Fig. 41) contains below the trochanter major, a specially strong smaller trochanter, which is absent in the cat. Tibia and fibula are complete in the cat (Fig. 43); in the rabbit (Fig. 44) they are only separated in the upper half.
The whoe carcass of the cat can be immediately recognized by its head, penis bone, and the tail, and for these reasons, if offered for sale, these parts are always removed on the slaughtered animal. Rabbits generally have the shot wounds, but these are naturally absent in the slaughtered domesticated rabbits. The meat of the cat is paler than rabbit meat; the fat of the cat appears whitish in contrast to rabbit fat, which is honey-yellow.
As it says, it has some explicit figures which you can go and see, showing the different bones of the one next to the corresponding bone in the other, so that you can easily see the differences.
If you don't speak anatomy, let me translate. See also the image below.
This is a 1908 book that tells food inspectors how to tell when someone is selling cats as hares/rabbits. They say that, for a true rabbit:
How will you see these? To look at the bones you can probably just stew one of the animals pretty hard until the meat is "just falling off the bone," then carefully pick the meat off.
Make sure before you use any of these criteria to conclude catness that you have seen the difference on between two images of skeletons. Sometimes the difference is rather subtle! For example in the images that Stephie has posted, you can very easily see the "shoulder-blade spike" (labeled #33) on the rabbit, but not on the cat, so this is a clear diagnostic criterion: if I didn't see it then I'd strongly suspect "cat". Similarly the fused/unfused bones are pretty decisive, as long as you don't accidentally remove the incredibly-thin tibia of the cat and then think "oh, I just see one bone, it must be fused." Be cautious until you compare to both.
I've taken an image from Flickr and updated it with some highlights of what this 1908 manual is suggesting you look for:
The simplest way to tell the difference is to look at the ribs.
Cats have one pair of floating ribs, but rabbits have three pairs. The floating ribs are the ones at the bottom (i.e. towards the tail), that are not attached to anything at their outer end. All the other ribs are either attached directly to the breastbone, or to the cartilage that extends from the base of the breastbone.
Cats have nine "true" ribs (attached directly to the breastbone), three "false" ribs (attached to the cartilage), and one pair of floating ribs. Rabbits have seven "true", two "false", and three floating. So cats have a total of thirteen ribs, but rabbits typically only have twelve (although it can vary).
This gives us a simple test:
The easy way is to look at skull, paws, and tail - but these are normally removed!
Cat have short paws, long tails, and a sleeker skull
Hares have very long rear legs, easy to spot
Rabbit have curved lower leg bones (tibia and radius?), shaped like this ()
Cats generally have quite straight lower leg bones, shaped like this V. The are nearly touching each other
The main differences I see in the skeletons of the two animals is that the cat's humerus (large single bone in the front legs) and its radius/ulna (smaller dual bones in the front legs) seem to be very close in length, or the single bone is slightly longer. The same goes for the hind legs, where the femur (single bone) and the tibia/fibula (dual bones) are of similar length or the single bone is slightly longer.
In the rabbit, the dual bones (radius/ulna in front leg and tibia/fibula in hind leg) are significantly and very noticeably longer than the single bones (humerus and femur, respectively). This is more evident in the hind legs, where the tibia/fibula combo seems to be about 20-30% longer than the femur.
As a child in the 1940's we were told that you could tell the difference between a skinned cat and a rabbit because one of them had kidneys side by side and the other's kidneys were staggered. I think the rabbits were side by side because they tasted delicious.
just take a look at the tail..! if(tail is long) then CAT else confirm RABBIT
