Tropical dome - Future outdoor aviary for douc langurs (maybe !)

One thing I really like about this new addition is that it breaks an unfortunately common theme in many Tropic Houses, a lack of outdoor enclosures. They very easily could have kept the langurs, harpy eagles or any other species indoors year round and no one would have complained, but I absolutely admire the zoo going the extra mile to give them outdoor access.

You are true but there is a big problem here : the species who need more the outdoor enclosure have not. I speak about pygmy hippos and giant otters.

I would argue that langurs need the outdoor access more than Pygmy hippos. Pygmy hippos live in thick rainforest where the environment in shaded and only dappled light gets through, just like in a rainforest house while langurs are often found in the canopy where more light gets through. Langurs are also much more energetic so need more space than hippos.

I don't agree with your explanation. This is a new building on a new site. As I always say, zoos don't have to do something if they don't have the space and the money for it. Here, they could have do things différents and propose outdoors for all the species needed. They made another choice and I think it's a pity.

But then what would go in the middle? They'd have to get rid of a few exhibits around the outside, and yes, although they had a blank sheet of paper, they still had constraints. They needed areas for keeper access, off show housing etc.
Furthermore, pygmy hippos are more susceptible to sunburn than their larger counterparts, which means that housing them outside can be risky. I just think that the langurs very more suited to an outdoor enclosure than the hippos or otters. Giant otters spend lots of time around a single burrow, spending the vast majority of their time in the water. This gives them added security against predators such as jaguars who are mainly land-based as well as because the river is where their prey is found (large fish, small caimans etc.) This means that 1. They don't need much land space 2. They need about as much space as is given in the indoor exhibit. I reckon its a really good exhibit for them and they don't need an outdoor one.

I can't understand such reasoning ! The contraints are not the problems. There are always contraints. They could have put the alligators or the terrariums in the center. Lots of exhibits could be transferred. And I don't agree with you about giant otters and douc langurs. The langurs need shadow and the outdoor aviary will be without any shadow. Regarding the giant otters, I have seen them in six different zoos, for a number of visit,s and I can tell you that they were not always in water (in my memory I can say half time on land and half time in water). The land space here is ridiculous without any vegetation. I'm not sure you want to take their place !!

Otters don't wander around in the forest, which is why there is no vegetation. I couldn't find one photo of a Giant otter in the rainforest, because they spend roughly half their time on the riverbank and half their time in the water. I reckon that a mulched/sandy beach area of around 200m2 is good enough for them especially if the pool is that large. Yes, a bit of grass could be nice, but it is difficult to grow grass beneath a walkway!
As for langurs, not sure where you found that langurs needed shade?
Anyways, all I'm trying to say is that a Giant otter outdoor exhibit, given the size and nature of the Dome is not really necessary given the circumstances, whereas I would argue it is much more so for energetic langurs.

But then again doucs travel more, while otters generally stay put for a while on the same stretch of riverbank moving along the river from time to time.