A fraction the size of its famous (and famously aggressive) cousin, the pygmy hippopotamus is an elusive, secretive creature which dwells in remote Western Africa. But while the animal’s preference for solitude means we don’t know how many remain in the wild, most estimates suggest there are only a few thousand left.
(Not sure if you care about the plight of the pygmy hippo? Watch this
blatant emotional blackmail video of a baby pygmy and tell us you don’t want to do all you can to help these creatures.)
Dr Gabriella Flacke is a veterinarian completing a PhD at University of Western Australia, and has been studying the pygmy hippo since September 2012. Presently Dr Flacke is in the USA, which has the largest population of captive pygmy hippos in the world, 70 (Australia has just five – two at Taronga Zoo in Sydney and three at Melbourne Zoo).
By studying the animals’ habitats, health and necropsy reports, as well as stud books, Dr Flacke hopes to improve captive pygmy hippos’ breeding rates and their lives in general.
Techly got in touch with Dr Flacke, who told us a little about her research, how little we actually know about the creature, and why the pygmy hippo’s elusive nature could help them survive humans encroaching on their habitat.
Your research has found that 40 per cent of captive pygmy hippos suffer from polycystic kidney disease (PKD). Do you have any hypotheses as to why?
First of all the study evaluating prevalence of PKD in pygmy hippos was retrospective, meaning all the animals in the study are deceased and the information comes from necropsy reports. I looked at a total of 179 adult animals (adult means three years and older) for which I had complete necropsy reports. None of the animals currently living in zoos are part of the PKD study as you can’t diagnose the condition in a living animal without ultrasound or MRI; not so easy in a pygmy hippo!
The overall prevalence among the 179 adults was 34.6 per cent. For pygmy hippos originally captured and imported to zoos from West Africa (53 adult animals), the prevalence was 45.3 per cent. For pygmy hippos born in captivity (126 animals), the prevalence was 30.2 per cent.
This high prevalence is very surprising, and very concerning. In humans, there are two known forms of PKD (autosomal dominant inheritance and autosomal recessive inheritance) and the overall prevalence of PKD is less than 0.0001 per cent. In some breeds of domestic animals, for example Persian cats, a higher prevalence is seen (I believe it’s around 30 per cent for Persian cats, but I would have to double check recent literature on the subject).
We do not know if PKD in pygmy hippos has a genetic inheritance pattern, but it’s very likely that it does. A lot of the affected animals are related. So in response to your question of why the prevalence is so high, if it is an inherited condition, then a few affected animals that had a lot of offspring could have passed it to a large number of additional hippos. Founder representation is not evenly distributed through the captive population. Founders are the ‘original’ animals imported from the wild. Some founder animals had many offspring, others had one or none. Also we assume that all wild animals are unrelated, but we have no way of knowing that. Trapping expeditions to West Africa often brought back several animals at once (up to a dozen or more), and the animals were usually all sourced from the sample place. So a group of founding animals may have actually been closely (e.g. father and daughter; full siblings) or distantly related (cousins, etc.).
There is also a hypothesis that conditions of captivity (e.g. diet, husbandry, longevity) somehow influence or speed-up the development of PKD that would not happen in the wild. Or maybe wild pygmy hippos die long before they are actually affected by PKD, and so it hasn’t mattered to them and they have lived with condition for thousands of years without any problems. No one knows how long they live in the wild, but in captivity it can be 40-plus years. Most animals with the condition are 20-plus years old, so they seem to be able to live with it for many years after it first develops before they become clinically ill. But the youngest affected animal in my study was 11.5 years old, so it can start earlier as well.
Hopefully someday we can develop a genetic marker for this condition so pygmy hippos can be screened while they are still alive and we may be able to reduce prevalence via selective breeding. The problem is we don’t have much non-affected founder stock left (e.g. unaffected genetic lineages), so where will we get new genes? Exporting more pygmy hippos from the wild seems unlikely, but perhaps future assisted-breeding techniques such as artificial insemination will help spread the ‘non-affected’ genes around the world more easily, as there are pygmy hippos on six of seven continents!
Do zoos around the world have breeding programs to try create genetic diversity in their pygmy hippos, or do they just make do with the animals they have?
Yes, they do, and for most species held in zoos (and definitely for all endangered species) there are programs in place to try and maximise genetic diversity by trading animals between institutions and even around the world. But, that’s expensive and logistically challenging for larger animals, so some (less financially flush) zoos sometimes have to make do with what they have.
And in the old days, that was certainly the case, so that would also have led to a significant amount of inbreeding in some cases, and also some animals that were ‘good breeders’ produced lots of offspring that then went to other zoos, but they would have all been related to the original pair of parents. There was one male pygmy hippo at Basel Zoo who is genetically represented in 10 per cent of the zoo population world-wide. That’s a lot of genetic representation amongst only 350 or so hippos!
You spent time in the Ivory Coast researching the pygmy hippo in its native habitat in April/May of 2013. The, uh, non-pygmy hippo has something of a reputation for being aggressive, during your time in Africa did you need to take particular precautions around the wild pygmies?
The other hippo is generally referred to as the ‘common’ hippo. Non-pygmy sounds pretty good, though!
Pygmy hippos are solitary, very secretive, and elusive. They live in dense rainforest where they would hear and/or smell you coming long before you can see them, and then they run off. The list of people currently alive who have seen one in the wild is probably less than 25, definitely less than 50. That excludes local people, of course, like hunters, farmers, loggers, and people who work in the forests. But even then, my field assistant in Ivory Coast had worked in Taï National Park for 15 years (he was Ivorian) and had seen two pygmy hippos.
Everyone I know who has ever seen one says it either ran away or dove into the water and disappeared within seconds. So no, they are not dangerous in the wild.
What spiked your interest in the pigmy hippo?
As a veterinarian, I obviously love all kinds of animals, but I have always especially loved hippos, every since I was a small child. The pygmy hippo is particularly interesting to me because it is so poorly understood and there is almost no scientific research about it in the wild.
First of all it’s nearly impossible to find; it is assumed to be endangered but we don’t know for sure as we don’t even know how many there are. Secondly it lives in a part of the world that isn’t exactly the easiest place to do field research. The weather is hot, humid, and oppressive. There are all kinds of fun diseases (including Ebola). The infrastructure of the range countries where it lives (Ivory Coast, Liberia, Sierra Leone, Guinea) isn’t exactly stellar. There has been much political unrest and civil war in the region. And during the rainy season it’s impossible to get anywhere in the rainforest as the ‘roads’ turn to rivers of mud.
Probably part of the reason it has persisted so long despite extensive loss of habitat and poaching is the inhospitable nature of its habitat and the fact that it is so shy, elusive, and enigmatic.
Realistically, is there hope for the pigmy hippo in the wild, or are zoos the best hope for the species on-going survival?
That’s a loaded question. Some might ask, at the current rate of human population growth and environmental destruction, is there hope for any species in the wild, at least long-term?
But I like to be optimistic. The pygmy hippo has survived all this time despite some pretty impressive obstacles within its home territory. I think as long as there is enough intact habitat, it will continue to remain the enigma in the forest and will not yet go the way of the thylacine or the dodo bird. But we can’t count on that, so the zoo population is viewed as an ‘insurance’ population, if you will. The same goes for many other endangered species whose habitat is disappearing at an alarming rate.
But our current insurance population of pygmy hippos is probably not the most genetically robust, nor is it reproducing very efficiently. So those are some of the problems I am trying to address. And hopefully improve captive hippo health and welfare in the process.