Sahel Hound

Theory

In 1887, Joel Asaph Allen posited a biological rule that warm-blooded animals in colder climates tend to have shorter limbs than the equivalent animals from hotter climates. Christian Bergmann, posited a similar rule in 1847. Bergmann’s rule is that the body mass of warm-blooded animals increases in colder climates.

Azelouan 110 degrees Fahrenheit

The mechanism behind these phenomena is thought to be temperature regulation. Warm-blooded animals have to maintain a narrow core body temperature range or they die. Surface area to volume ratio is a critical factor in heat transfer. A low surface area to volume ratio tends to retain heat while a high one tends to radiate heat into the environment. This effect is the reason that car radiators and the heat exchanger in an airconditioner have huge surface area.

Surface and Volume

Shape controls the ratio of surface area to volume. A sphere is the shape with the minimum surface area for volume while a flattened pancake has close to the maximum surface area for volume. This is oranges burst when you squeeze them. As the orange flattens, its volume stays constant but the skin must stretch. Eventually you exceed the elasticity of the skin and the orange bursts.

Another example is a stack of 8 sugar cubes (1cm x 1cm x 1 cm). If you stack the cubes 2 x 2 x 2, then the volume is 8 cubic cm and the total surface area is 16 square cm. If you stack the cubes in a 1 x 2 x 4, then the volume is still 8 cubic cm but the total surface area is 22 square cm.

Azawakh Morphology

Azawakh are medium-sized hounds in the range of 40-50 pounds. That makes them the same mass as a Norwegian Elkhound but about 7 inches taller. That’s Allen’s rule in play. An English Greyhound is of roughly similar height to an Azawakh but weighs 20-30% more. This is Bergmann’s rule in play.

To use a car metaphor, the Elkhound has the same size engine but a much smaller cooling system and the Greyhound has the same cooling system but a much larger engine. The flat, dry musculature, long legs and high tuck of the Azawakh are all adaptations for heat tolerance.