I was both amused and irritated to see this photograph in a gallery of animal images at the Telegraph. (Click it for a larger view.)
The caption read: " A hippo yawns in Chobe National Park in Mozambique". Unfortunately, it's not correct. For a start, Chobe's in Botswana, not Mozambique - but then, what's a thousand-mile error between friends? Secondly, and more seriously, that's not a yawn. That's a threat display. The hippo is showing its fighting tusks, ivory 'teeth' that can tear great chunks out of a rival hippo, or dismember a crocodile . . . or rip you apart if you provoke it. That's what its actions are saying to the photographer. "You worry me. If you come any closer, I'm going to do something about you - and you won't enjoy it!" Look at the animal's only visible eye. It's not closed or screwed up, as is natural in a yawn. It's looking right at the photographer to see if he/she got the message.
During my many years in Africa it never ceased to amaze me how absolutely, blindly stupid tourists could be about animals. They would never believe our warnings, thinking that we were joking with them or trying to scare them. When (as inevitably happened) some of them got into difficulties, their reaction was to blame us for not warning them sufficiently! Let me give you a couple of examples.
A group of kayakers from Europe decided to travel down the Zambezi River. I was present when they were warned about precisely the kind of threat display illustrated above, and told explicitly, "Don't paddle too close to hippos - they won't like it, and they'll attack." One of them actually had the gall to laugh at us and mention the dancing hippos in Walt Disney's 'Fantasia'!
Unfortunately, Disney's dancers had (and still have) nothing whatsoever to do with reality. At least one of the kayakers didn't listen, as was demonstrated a few days later when he paddled too close to a hippo. His body was never found; the crocodiles probably got whatever the hippo left. The remains of his crushed, well-chewed canoe were recovered a few miles downstream. (Yes, his traveling companions vociferously blamed local authorities for not signposting the river at least every mile concerning the dangers of hippos, crocodiles and ingrown toenails . . . after all, they couldn't be expected to believe verbal warnings from ordinary people like us. We weren't 'official'. We weren't certified experts!)
In another incident, a female tourist from the USA visiting a game reserve spotted a small lion cub on the other side of a fence. (Its mother was recovering from injuries, which is why the two of them were in the protected enclosure.) Before the astonished guide could stop her, she put her arm through the fence to try and pet it. Its mother, hitherto unnoticed in the bushes just beyond the cub, must have assumed she was trying to harm her cub, because she promptly ripped the flesh from the woman's arm. Only bones and a few tendons were left; what remained had to be surgically amputated. The woman actually had the gall to try to sue the game reserve for not posting warning signs and armed guards to prevent her from doing something like that - this despite having been clearly and repeatedly warned during the introductory lecture, prior to the walking tour, not to approach, pet or talk to any animals whatsoever!
So . . . a hippo, yawning.