Mrs May replied by thanking her for her service (inset left).
But the departure is another second brutal body blow for Mrs May, after Defence Secretary Sir Michael Fallon resigned over the Westminster sleaze row seven days ago.
The image was posted on Twitter by Daniel Schneider, a biologist from Boston. Nevermore.' His tweet has received almost 36,000 retweets, and over 1,000 replies.
Mr Schneider wrote: 'Want to know what extinction looks like? The photo comes months after Sudan appeared as an ad on dating site Tinder, in the hopes of raising vital funds towards breeding methods for the species.
Secretary General Jens Stoltenberg called for the infrastructure update as NATO is set to overhaul its command structure for the first time since the Cold War, allegedly in response to Russia's 'war games'.