I’m not sure I’d necessarily blame humans. A hybrid between two species that are in different genera, which diverged over 6 million years ago, and which have different numbers of chromosomes, would likely have had any number of genetic abnormalities which could have caused it to die. “Hybrid vigour” only works up to a certain point, generally only within a species. Once hybridisation occurs outside the species, more health issues rather than less appears to be the norm.
Animals are pretty good at hiding when they're sick, though, and this was an animal that had also been hit by a vehicle previously. There could well have been something going on with it that wasn't visible to keepers who only saw it behaving normally. Just as an example, say its unusual genetic makeup made it predisposed to aneurisms. It would have looked fine right up until it wasn't.
It may have been human fault, but it could easily not have been as well. The lack of details of cause of death being released isn't conclusive: a lot of animals in zoos in Europe and the US don't have publically released causes of death either. So I'm not going to assume that an extremely unusual hybrid animal died because of human maltreatment when there are other explanations that also make sense.
Vets have to balance up the benefit of testing for health problems in a seemingly healthy animal vs the physical and emotional stress caused to the animal by subjecting it to tests. If it looks like it's recovered from being hit by a car, they're not going to transquilise it and do an MRI just in case it has a blood clot or aneurism. Any vet will tell you that knowing what's going on with an animal medically involves a lot of guesswork, and animals that seem healthy can turn out to have something seriously wrong with them that wasn't picked up by a vet until it was too late.
They probably would have done one when it was brought in, but animals have to be anaesthetised to have tests like that done (they can't be told to lie very still the way humans can). Since anaesthesia comes with a risk of death just on its own (it does in humans too!), it's not something you do unless you have to. So yeah, when the animal was first brought in after the accident, they probably did do MRIs and/or X-rays because it would have been medically necessary. But they wouldn't have done them again later if the animal seemed to be recovering from its injuries, because they'd have risked killing it in the process. It's a very real possibility that there was some residual internal injury that wasn't obvious at the time it was injured, but which caused it to die a few months later.
Plus, yeah, it was an unusual hybrid, and there's no way of knowing how that affected its health. What happens with hybrids sometimes is, say, Species A has a gene that causes a health issue and a gene that fights the health issue. Species B has neither gene. So when Species A and Species B mate, the offspring can end up with a gene that causes the health issue, but no functioning copy of the gene that fights it. Thus, it gets the health issue and then dies. Sometimes this is obvious shortly after birth - it's not uncommon for hybrid animals to die within days or months of birth. But sometimes it's the kind of health issue that takes a year or two to cause a serious enough problem that the animal dies. Maybe with this animal the combination of genes it had affected how it healed from its wounds, leading to it dying of something a pure dog or pure fox would have recovered from.
I’m not sure I’d necessarily blame humans. A hybrid between two species that are in different genera, which diverged over 6 million years ago, and which have different numbers of chromosomes, would likely have had any number of genetic abnormalities which could have caused it to die. “Hybrid vigour” only works up to a certain point, generally only within a species. Once hybridisation occurs outside the species, more health issues rather than less appears to be the norm.
True, but given that:
I’d say the odds are that it was human fault.
Animals are pretty good at hiding when they're sick, though, and this was an animal that had also been hit by a vehicle previously. There could well have been something going on with it that wasn't visible to keepers who only saw it behaving normally. Just as an example, say its unusual genetic makeup made it predisposed to aneurisms. It would have looked fine right up until it wasn't.
It may have been human fault, but it could easily not have been as well. The lack of details of cause of death being released isn't conclusive: a lot of animals in zoos in Europe and the US don't have publically released causes of death either. So I'm not going to assume that an extremely unusual hybrid animal died because of human maltreatment when there are other explanations that also make sense.
I'd agree, except vets were involved and (apparently?) gave it a clean bill of health.
Vets have to balance up the benefit of testing for health problems in a seemingly healthy animal vs the physical and emotional stress caused to the animal by subjecting it to tests. If it looks like it's recovered from being hit by a car, they're not going to transquilise it and do an MRI just in case it has a blood clot or aneurism. Any vet will tell you that knowing what's going on with an animal medically involves a lot of guesswork, and animals that seem healthy can turn out to have something seriously wrong with them that wasn't picked up by a vet until it was too late.
Well, I'm not an expert I guess. They really wouldn't even do an MRI? It seems like that's a serious situation where you'd want to start with that.
They probably would have done one when it was brought in, but animals have to be anaesthetised to have tests like that done (they can't be told to lie very still the way humans can). Since anaesthesia comes with a risk of death just on its own (it does in humans too!), it's not something you do unless you have to. So yeah, when the animal was first brought in after the accident, they probably did do MRIs and/or X-rays because it would have been medically necessary. But they wouldn't have done them again later if the animal seemed to be recovering from its injuries, because they'd have risked killing it in the process. It's a very real possibility that there was some residual internal injury that wasn't obvious at the time it was injured, but which caused it to die a few months later.
Plus, yeah, it was an unusual hybrid, and there's no way of knowing how that affected its health. What happens with hybrids sometimes is, say, Species A has a gene that causes a health issue and a gene that fights the health issue. Species B has neither gene. So when Species A and Species B mate, the offspring can end up with a gene that causes the health issue, but no functioning copy of the gene that fights it. Thus, it gets the health issue and then dies. Sometimes this is obvious shortly after birth - it's not uncommon for hybrid animals to die within days or months of birth. But sometimes it's the kind of health issue that takes a year or two to cause a serious enough problem that the animal dies. Maybe with this animal the combination of genes it had affected how it healed from its wounds, leading to it dying of something a pure dog or pure fox would have recovered from.
Thanks for replying, all very interesting!