Interesting new paper for those studying animal physiology:
Penguins are supremely adapted to life in the extreme conditions of the Antarctic, from their thick plumage to huddling behaviour. Using thermal imaging this paper in Biology Letters (http://rsbl.royalsocietypublishing.org/content/9/3/20121192.short?rss=1) demonstrates how Emperor penguins use their well insulated trunk to manage body heat loss in brutally low temperatures. The temperature of the feathered outer surfaces can fall below the surrounding air due to radiative cooling. Heat is lost only through the relatively exposed flipper and head regions – perhaps it is important to maintain some comparatively unfeathered areas in case of overheating?
When considering the evolutionary and physiological significance of adaptations like penguin plumage it is useful to consider how temperature changes affect energy usage in animals. One way of appreciating this is to measure the animal’s ‘thermo-neutral zone’. Since mammals and birds are homeothermic endotherms they maintain a set, relatively high body temperature at which their biochemical processes are optimised. If the ambient temperature falls, animals need to produce heat, increasing their metabolic rate, or rate of energy expenditure. Conversely if it becomes too hot, strategies such as sweating or panting are employed to maintain body temperature, again increasing metabolic rate. In the laboratory we can calculate how much energy is expended by animals in a range of temperatures by measuring how much oxygen they consume. The range of ambient temperatures that does not elicit an increase in metabolic rate to maintain the ideal body temperature is called the thermoneutral zone. This concept is important when we consider the example of adaptation in bird beak size. While heat loss from the exposed beak is undesirable in the cold Antarctic, (reflected in a reduced bill size in penguins), what about birds that live in warmer climes? In the tropics, the toco toucan uses it’s large bill as a heat exchanger, a mechanism analogous to large elephant ears, to maintain it’s optimum body temperature when ambient conditions fall outside the thermoneutral zone. The bird uses countercurrent heat exchange in the blood vessels supplying the bill to modulate heat transfer with the environment. As you can see in the picture below, the bird reduces heat loss in cooler temperatures and increases heat radiation when too warm.
Figure taken from the 2009 paper in Science (http://www.sciencemag.org/content/325/5939/468.full?sid=402de1be-c045-4cb1-8a27-b6d88892d42f)
This video from Natalie Beresford (First Year). Why might this cockatoo dance? Is it like a bored tiger or an emprisoned polar bear, or is there something else going on? Why does it do the bow at the end?
Migration continues to fascinate scientists, dissecting the sensory cues involved, and the innate vs learned components. This open access article in PNAS looks at the ability of birds to migrate across the whole of the North American continent. There seems to be a mixture of learned and innate factors, with adult birds alone having a “map” of the whole continent.
Our very own Jonathan Codd features in this BBC news page, describing his work on the bones involved in dino breathing. The paper this was based on has just been published in the Proceedings of the Royal Society (open access).
Filed under Birds, Dinosaurs
After last week’s success with the video of the nutty Manakin bird, Per Smiseth sent in this link, which is to the Internet Bird Colection – a site that aims to assemble videos of every bird alive… Some very cool animals here!
Definitely a video that will make you laugh! The male red-capped Manakin (Pipra mentalis), a bird found in Costa Rica and Belize (watch out for it if you go there on the Field Course), does a rather cool moonwalk as part of its courtship ritual. It also produces some rather bizarre clicks with its wings. Two YouTube videos show these behaviours:
Researcher describes her work on the Manakin, including excellent high-speed film of how the wing-clicking, concluding with an odd imitation and a rather obvious M Jackson soundtrack.
Better footage, but the English soundtrack has been irritatingly overdubbed in what my ignorant ear thinks is either Russian or Polish. The bird will make you laugh, though.
Click here and see.
Filed under Birds, Videos
This story appeared on the BBC website and the national press today. What’s wrong with it? My 9-year old daughter spotted it straight away (which is obviously more than the journalists did!). Clue: you’d only have to change one letter to get a more likely explanation.
“Visitors to a Somerset stately home have been warned to keep away from a peacock – after he seriously damaged a luxury car he mistook for a mate. The amorous bird caused £4,000 worth of damage to an employee’s Lexus in the grounds of Sir Benjamin Slade’s country manor, Maunsel House, near Bridgwater. “It started when he fell in love with a Lexus, which was in a very distinct peacock blue,” said Sir Benjamin.”
Seems like a daft question, but the genetic bases of these effects can be quite simple. This article from Science (subscription needed to get past abstract) gives an example from pied flycatchers and shows that the genes are sex-linked. There’s also this summary in the same issue (same rules apply). Thanks to Per Smiseth for this.