This black rhino, Elly, has been part of a breeding program at the San Francisco Zoo.
It’s probably no surprise to regular readers that I have a soft spot for rhinos. This particular rhino, Elly, single hooved-ly pointed my life in the conservation direction. They are amazing animals. This post is going to primarily focus on black rhinos like Elly here, unless I specify otherwise, although much of the information will be true for most of the rhino species.
For example, all rhinos had enormous ancestors, including the largest land mammal that ever lived, the Indricotherium, which went extinct 10 million years ago.
A life size model of an Indricotherium, an extinct mammal. Image taken at the California Academy of Sciences.
One of the things that animals in this group have in common is their hooves, which have three toes and make a print like the ace of clubs. Notice how this rhino has very similar feet to the Indricotherium model:
A black rhino. Image taken at the San Francisco Zoo.
This group also has a really tough, very thick skin. Their skin is so thick that they are protected from thorns and can travel through dense thorn bush where other animals find it hard to travel. Other animals can then take advantage of the paths created by the rhinos.
A close up of the thick skin of a Greater one-horned rhino, Gauhati, at the San Francisco Zoo.
This is the skin of a Greater one-horned rhino, which has a scientific name that always makes me smile- Rhinoceros unicornis. On this particular rhino, if veterinarians have to give him an injection, they must do so behind his ear, where the skin is thinnest, or else their needles won’t penetrate the very, very thick skin.
Caring for their skin is a very involved process for black rhinos. First of all, they can be infested with over 20 species of skin parasite, including ticks and worms, which bite their skin and suck their blood. They can also get sunburns and since they don’t sweat, they overheat easily. Rhinos deal with these problems in a number of ways. The first is wallowing. Rhinos will roll around in mud to cool off and when it dries, it protects their skin from sunburn and parasites. However, baby rhinos won’t go into the mud wallows until they are big enough to climb out and nursing moms won’t go in everyday, probably to keep close to her baby and to keep her teats clean. This is just one of the many sacrifices a mother rhino makes for her young. However, they will roll around in dust.
Apparently, mom's sacrifices don't go unappreciated. Image given to me by the San Francisco Zoo.
Another thing black rhinos will do for skin care is rubbing, which also helps get rid of parasites. They will often use the same rubbing sites for generations and favorite rubbing posts can become practically polished over time. But, all the rubbing and wallowing won’t help them in one particular spot. They can’t quite reach behind the “elbows” of their front legs and rhinos frequently have sores there that can sometimes get infected.
Rhinos also have helpers in their skin care. The most well known is probably the ox-pecker-a neat little parasite eating bird.
An ox-pecker perched on a branch. Image taken at the Oregon Zoo.
These birds will climb all over a rhino and pick at its skin, ears and nostrils and of course, the rhino doesn’t bother them. When ox-peckers feed on antelope, they will take little bits of fur to line their nests, but when they feed on rhinos, all they get is the chance to eat parasites. Still, that’s sometimes enough for them. These ox-peckers will also fly and squawk loudly when danger is near, so they are also a good alert system for the rhinos as well. (While most full grown rhinos have nothing to worry about, lions will sometimes catch older or sick rhinos and calves are always at risk-1 in 6 rhino calves die in their first two years of life. Hyenas are often the cause because they can team up to get around mother rhinos who will aggressively defend their calves.) Unfortunately, ox-pecker numbers have seriously declined in southern Africa because farmers have been using pesticides on farm animals and the birds die from eating poisoned ticks on domestic cattle. The good news is that the birds are now being reintroduced in areas where pesticide use has been reduced.
Perhaps a more surprising rhino helper is a terrapin, a shelled animal closely related to turtles and tortoises. The terrapins live in waterholes where the rhinos wallow and then pull ticks from the rhinos’ skin underwater. Dung beetles also help rhinos, in an indirect way. Remember those sores behind the rhinos’ front legs? A particular parasitic worm loves to dwell is that little safe zone and this worm reproduces in the rhino’s dung. When a dung beetle carries the dung away, it takes the worms away with it. So rhinos have a few helpers to maintain their beautiful skin.
Another feature some rhinos have is a prehensile or partially prehensile upper lip.
A greater one-horned rhino, Gauhati, extending his prehensile lip to receive a carrot. Image taken at the San Francisco Zoo.
This is what Gauhati, the San Francisco Zoo’s greater one-horned rhinoceros looks like with his prehensile lip extended. Here’s what he looks like once he’s pulled his lip back in:
Gauhati after receving a carrot from my husband, Trey. Image taken at the San Francisco Zoo.
Rhinos will pull down branches with their horns and use their prehensile lip to grab twigs and leaves and twist branches until they break. Pretty much any form of bush or shrub within reach is food for a rhinoceros, right up to the thorniest acacia. After a fire on the open plains, rhinos have even been observed eating wildebeest dung, possibly because they were short of the minerals they needed or maybe because they couldn’t find any other food and wildebeest don’t digest grass well.
A black rhino at the San Francisco Zoo.
The last rhino feature I’m going to mention is the cause of death for many, many black rhinos. I’m speaking of course of their horn. Rhino horns are made out of compressed hair, but are still incredibly strong. Charging rhinos can poke a hole through a car door. Various cultures have different uses for rhino horn, including for use in traditional medicines or as dagger handles (thanks to education programs, this practice is becoming increasingly rare in Yemen) and since rhino horn is a real status symbol, people pay a small fortune for them. You might recall in a previous post about poaching I mentioned that poachers have high end technology, including helicopters and night vision. If we’re to prevent this animal from going extinct, we have to arm their guardians with advanced technology as well and continue education programs in countries where rhino horn is used. The poaching won’t stop as long as it is such a lucrative industry.
If you would like to help rhinos, there are a number of organizations that you can donate to that provide for rhino rangers, anti-poaching units, equipment for monitoring rhino populations and for breed and release programs. The International Rhino Foundation is a great one. One of the easiest things we can do and my personal favorite is an annual fundraiser put on by the American Association of Zookeepers. It’s called Bowling for Rhinos, and 100% of the profits gets dispersed among various reputable rhino conservation organizations. Follow that link and you can learn where Bowling for Rhinos is taking place near you; enjoy bowling, pizza and friends while saving rhinos. It’s a lot of fun.