By Fiona Hodge

What has the striped legs of a zebra and the brown body of a donkey? The ‘zedonk’ born last week to a female donkey and a male zebra at a US wildlife preserve. The founder and manager of the preserve, C.W. Wathen, was extremely surprised when the pregnant donkey gave birth to a partially striped baby. “We noticed it had stripes, and we just couldn’t believe it, we thought after momma cleaned it, it would be different. But it never was…”

Although there are no reported cases of zedonks here in New Zealand, at least nineteen other hybrids have been identified and genetically confirmed. We have a diverse bunch of hybrids, including small alpine flower hybrids, fern hybrids (e.g. the hen and chicken fern), flax hybrids, tree hybrids, seaweed hybrids, insect hybrids, bird hybrids, and fish hybrids. Unfortunately none yet have catchy amalgamated names.

Scientists say that hybridisation, the mating of individuals from two different species, is a surprisingly frequent occurrence. They have estimated that 25% of plant species and 10% of animal species are currently producing hybrids in the wild, although usually in very, very low numbers relative to parent species populations.

New Zealand rivals to the zedonk include the love children of Carpophyllum maschalocarpum (the thicker one) and Carpophyllum angustifolium (the thinner one). Find them in the East Cape, in Leigh, and probably other northern North Island locations.

So what does this hybridisation mean for our biodiversity? The impact varies dramatically, depending on the hybrids. Where hybrids can mate with the parental species they can transfer exciting and useful genetic adaptations between species. This has happened in our beech trees: red beech and hard beech have both historically acquired genetic material from the mountain beech via hybridisation.

Alternatively hybridisation can pose a conservation threat to one or both of the parental species. Our native black stilt or kaki is critically endangered, and has developed a bad habit of mating with the pied stilt or poaka. Keeping pied stilts out of kaki breeding grounds has played a part in growing the numbers up from just 23 birds in the 1980s.

Hybridisation can also produce entirely new species! This requires hybrids to be fertile, but unable to mate with either parental species… a relatively rare set of conditions. Here at home hybridisation has created eight species of entirely female stick insects, as well as new species of everlasting daisies, North Island buttercups, spleenwort ferns and shield ferns.

So if you’re excited about the baby zedonk, skip the trip to the states and head out into the mountains, forests, and coasts of New Zealand. Hybrids occur in all your favourite holiday spots too, from flax hybrids in the Marlborough Sounds to seaweed hybrids on the East Cape.