I still believe well over half of those animals are kept by and at Rum Creek. By my estimates (which may well be incorrect), there are somewhere around 40 pygmy hippos in public AZA and AZA-affiliated zoos, give or take a few hippos. Meanwhile I know there are over 70 at Rum Creek alone. I wouldn't be surprised, though, to learn that there are more pygmies in AZA zoos though despite Common having a slight gain on number of holders due to their smaller size making it easier for zoos to hold additional individuals.
Massive life support systems are often only needed on this scale at zoos where clear underwater viewing is included. It's one of the biggest arguments for why underwater viewing is unnecessary, in fact. These systems due take up way too much space and cause the price of the project to skyrocket. Take the new exhibit at Cincinnati discussed some pages back now, where the size of the animal space is so small the zoo cannot comply with AZA regulations of minimum three individuals meanwhile the size of the filter room dwarves the animal space. I don't think there's any doubt that the expense of underwater viewing for hippos may be a factor in why new zoos might be hesitant to pick up Common Hippos, however I've yet to see any evidence that this in any way is connected to a trend of many US zoos phasing-out Common Hippos in favor of pygmy (or even phasing-out with no plans for them to return in general) as
@Emanuel Theodorus seems to believe.
Additionally, I don't really think there's going to be
that much of a difference in expensive between needing a filtration for Common Hippos and needing it for pygmy hippos. The major different is more on the level of other resources. Feeding, housing, maintenance, exhibit space, keeper care, etc. Pygmy hippos are simply a lot less resource intensive than their larger relatives.
It is perhaps worth noting that underwater viewing does not inherently need crystal clear water. Sedgwick County's hippos have underwater viewing but the doesn't appear to be filtered much, if at all. Of course, this then leaves you with
a pretty unappealing view.
The expense of filtration aside, there are other factors which may cause zoos to lean away from investing in Common Hippos. We've already discussed things such as pygmys being smaller, more easily managed, less resource intensive, more endangered ,and more readily available within the AZA, but there's also the issue of the modern standard of care we've accepted for Common Hippos which most pre-existing hippo holders simply do not fall in line with. Maybe there is one, but I've yet to find a truly great hippo exhibit in American zoos. Historically, most American hippo exhibits have looked like this:
Nile Hippo Exhibit - ZooChat (Fort Worth, now replaced)
New Nile Hippo Exhibit - ZooChat (Philadelphia, opened in 2010 or 2011)
Hippopotamus Exhibit - ZooChat (Los Angeles, due for demolition)
These enclosures generally feature average-sized pools and small, barren land areas. Hippos spend much more time on land than they've historically been given credit for, yet we have precious few exhibits in this country that can offer this. Even newer hippo exhibits with underwater viewing such as at Cincinnati (for which there appear to be no photos of the new exhibit on ZooChat?), Dallas, San Antonio, San Diego, etc. generally lack the land space these animals should actually have. The country's best hippo holder is probably Disney with their Kilimanjaro Safari habitats:
Kilimanjaro Safaris - First Hippo Exhibit - ZooChat
Kilimanjaro Safaris - Second Hippo Exhibit - ZooChat
But even these offer virtually no land space despite the excellent pool size. Not to mention, DAK aside, there are very few hippo holders here which can meet the rule of a minimum three-large herd. Most zoos manage two, which appears to be the max most of these habitats, even at zoos like San Diego, San Antonio, and St. Louis, can handle. While I've not been there to confirm myself, my understanding is the only major US zoo that has properly satisfied these two major needs for keeping Common Hippos in a modern facility is Memphis, where they care for four animals in a habitat with a sizeable pool (with underwater viewing) and provide a decently-sized land portion. Also, judging from the plans for Fort Worth's new hippo exhibit, their hippos
might have access to the Black Rhinoceros yards overnight. If this is the case, then FW probably has the best hippo exhibit in the country but they'd still fall short of the minimum herd size requirement the AZA has established.
Now, all of that said, while these factors are surely deterring many zoos from wanting to add Common Hippos to their collection in the future, is there really any evidence of a noticeable decline of hippos in American zoos as was claimed? There aren't many major US zoos that already have or have upcoming plans to phase-out their Common Hippos without expressing the desire to reobtain them in the future. It's already been mentioned that while LA will be sending off their hippos in the future, they also have them returning on their masterplan. Fresno Chaffee phased-out hippos over 15 years ago, but they also plan on bringing them back in. Philadelphia has a pretty bad hippo exhibit, but rather than phase them out they are looking into ways to fit a new, more modern hippo facility into their masterplan. Dallas opened their new exhibit in 2017, Fort Worth opened theirs in 2018, Cheyenne Mountain opened their new exhibit just last year, and Nashville recently announced their plans to bring in the species for their upcoming African expansion.
Meanwhile, we have Tulsa and John Ball opening new pygmy hippo exhibits in the near future but that's about it. The former is also using this as a new exhibit for their Diana Monkeys. Bronx has expressed interest in the species but there are no known plans solidified for this. The only zoo I know of which may opt to phase-out Common Hippos while bringing in pygmy is Sedgwick County, but this remains to be seen. Otherwise, the latest zoos to pick up this species are non-AZA (Wildlife World, Tanganyika, Metro Richmond).
~Thylo
Luckily there’s no chance of that. The exhibit will be similar to their Amazon Rising complex, which puts a huge focus on being naturalistic.
