Us ape lovers cannot pass up this thread:
This a 2001 issue from Singapore honouring Ah Meng, a Sumatran orang-utan female given to the zoo in 1971. She died, a much loved legend, in 2008 - by then, she was a great-grandmother.
while the above is from a 1988 set of 8 of Tanzania,called "Wildlife". Interestingly, it included a dinosaur ... but I have come across them in "Endangered" issues, occasionally ...
Finally, another ape, from Burundi, 2011: