I don't follow.
Quite honestly, it's a lot more likely that all the weird cryptic animals that people claim to see these days (La Cupacabra, Nessy, Bigfoot, Mothman) are different species of animals we already have today, but in the same genus. I don't see why this is so far fetched, it makes a lot of sense in explaining how they could go unseen for so long.
People who have been looking for what we call La Cupacabra have been looking for stuff looking like this

Not something like in the picture, which could easily be mistaken for a dog or rat.
There are a ton of animals and creatures on this planet that we don't know about, but I would say that it would be a ton easier for an animal like one in the article to go unnoticed as opposed to our generic picture of la chupacabra that's been painted as an alien or amphibious thing.
Instead of "bigfoot", just a weird looking monkey/ape, or even a bear. Instead of mothman, a large bird. Just because the discovery channel paints odd and far out pictures of all these things, doesn't mean that they can't be conventional.