Mysterious echidna in London, England museum

This 17 June 2019 video from England says about itself:

What’s wrong with this echidna in the collection? | Natural History Museum

Echidnas are unusual among mammals, laying eggs and producing milk for their young.

But they might be more quirky than you think, with one particular feature confusing scientists in Europe when they saw one for the first time.

The Natural History Museum in London is home to over 80 million specimens, including meteorites, dinosaur bones and a giant squid.