When rangers at a Kenyan national park first glimpsed a tawny foal alongside its zebra mother, they assumed the newborn had been wallowing in a mud bath.

A closer look, however, revealed the surprising truth: the mare had given birth to a rare zebra-donkey hybrid known as a zonkey.

The Sheldrick Wildlife Trust (SWT), which reported the discovery, said the birth was “highly unusual” but it was “not difficult to connect the dots” to establish the young zonkey’s paternity.

The mother is assumed to have been impregnated after straying out of Tsavo East National Park and into a neighbouring village more than a year earlier.

“She made herself right at home there, becoming an honorary member of a local woman’s cattle herd,” said the SWT, an animal rescue group which was asked to transport the “wayward” zebra back to a protected area several weeks later in May last year.

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By this point, the trust said, the zebra had become “fairly habituated to community life” so was resettled close to the base of its anti-poaching team in Chyulu National Park where rangers could keep an eye on her.

She was seen frequently over the following months, and in early this year fence maintenance workers glimpsed the tiny foal by her side.

“It wasn’t until several weeks later that we finally got a proper sighting of the pair — and that was when her birth announcement revealed a whole new, surprising twist,” SWT said.

“During her time living within the community last year, she had obviously become acquainted with an amorous donkey.”

The young zonkey has the sturdy body of its donkey sire and the striped legs of its zebra mother. Like mules, it will be unable to breed once it reaches maturity, but the SWT said it “should otherwise lead a normal life”.

The conservation group said both mother and baby were “thriving” in a region with relatively few predators, plentiful water and lush vegetation.

It added: “They seem quite content to spend their days grazing side-by-side, a sight that makes us all stop and marvel at the wonders of nature.”