Dear Readers, I don’t know what it is about birds, but much as I like them, they don’t always like me. As you may remember, I was chased by a goose when I visited a City Farm, and when I went for my first ever visit to South Africa, our jeep was hotly pursued by a male ostrich, which was a bit like being hunted down by a velociraptor. Gosh, those creatures can run! And they know all the short cuts! I remember our jeep bumping over potholes and careering through bushes. We’d stop, thinking we’d finally outrun Mr Ostrich, only to hear the telltale thumping of his feet as he accelerated towards us. As he was more than eight feet tall on his tippy-toes and had already given someone a nasty peck on the head, we were all semi-traumatised by the experience. For the rest of the trip, the sight of an irate hippo or a prowling lion didn’t bother us, but we’d all shriek at the sight of an ostrich. It feels a bit like the chicken’s revenge.
Anyhow, I was fascinated by this article in New Scientist this week, which is all about the neck of the ostrich. Large animals tend to have more problems with rapid temperature changes because they can’t lose heat quickly (if you all remember your surface area to volume from school biology lessons). Different creatures evolve different methods to deal with this, like the enormous flappy ears of the African elephant. For the ostrich, the key seems to be that their necks act as a radiator.
Erik Svensson, from Lund University, Sweden, spent five years taking infrared photographs of ostriches at a research farm in Klein Karoo, South Africa, and discovered that the ostrich’s neck acts as a ‘thermal window’, emitting heat when it’s too hot, and retaining it when it’s too cold, thus keeping the temperature of the head and brain stable. Our guide on our ostrich-embellished South Africa trip told us that the birds only have a brain the size of a walnut, and was very disparaging about them. However, as the ostrich had reduced a whole jeepload of English tourists to jabbering wrecks I think he might have underestimated them.
The research farm has three different subspecies of ostrich, one from Kenya, one from Zimbabwe and one from South Africa. Interestingly, the ones from Zimbabwe and South Africa, where there is more climatic variation, seem to be better at shifting the temperature of their necks. Furthermore, female ostriches who had a greater temperature difference between their necks and their heads laid more eggs in the following period than ostriches with a smaller difference, implying that the neck is a buffer for heat stress. After all, keeping our brains from frying is important for any species, hence the need for sunhats and for none of that ‘mad dogs and Englishman going out in the midday sun’ stuff.
Ostriches also pant, and Ben Smits at Rhodes University in South Africa wonders if the hot blood from the neck is actually shunted upwards and then cooled when the animal opens its mouth, as happens with dogs (and humans).
Scientists speculate that as the climate gets warmer, the neck of the ostrich could get even longer – this appears to be a genetic adaptation, and so it can be passed on through the generations. It’s clearly beneficial for the ostrich, both in terms of survival and of reproductive success. I’m not sure exactly how I feel about an even taller ostrich than the one that we met, but maybe next time I’m planning visiting somewhere which has ostriches, I’ll take a tin hat (though that might just lead to my brain overheating).
Photo One by Bernard DUPONT from FRANCE, CC BY-SA 2.0 <https://creativecommons.org/licenses/by-sa/2.0>, via Wikimedia Commons
Photo Two by Benh Lieu Song from https://www.flickr.com/photos/blieusong/7234068808
Photo Three by Donarreiskoffer, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons