Why Does the Inland Taipan Change Color? Seasonal Shades

How does the inland taipan’s color change?

The inland taipan is one of the few snakes known for a clear seasonal color change. In summer it is usually pale: light brown, olive or even straw yellow, sometimes described as fawn. As the weather cools in autumn and winter, it darkens to a rich, deep brown.

The head and neck show the biggest difference. They are always darker than the body, but in winter they become glossy black, while in summer they fade to dark brown. Many scales on the back have dark edges that line up into a broken herringbone or chevron pattern, and this pattern is easiest to see on a pale summer snake.

The change is slow. It happens over weeks and months, not minutes. Because a single snake can look so different at different times of year, color alone is not a reliable way to identify it.

Why change color? The heat explanation

Reptiles are ectotherms: they cannot make much body heat of their own and depend on the sun and warm surfaces to reach the temperature they need to move, hunt and digest food. Their color affects how quickly they gain heat. Dark surfaces absorb more sunlight, and pale ones reflect more of it.

The inland taipan lives in the Channel Country of central-east Australia, on the border of Queensland and South Australia. The climate there swings between extremes. Summer days are often above 40 °C (104 °F), while winter nights are cold and can drop close to freezing. A snake that can be dark in the cold months and pale in the hot months gets the best of both.

The Australian Museum and other authorities describe the change in these terms: the dark winter color presumably helps the snake warm up quickly, and the pale summer color helps it avoid overheating. This is the widely accepted explanation, though it has not been tested in detailed experiments on this species. That is not surprising for a snake that lives in such remote country and spends most of its time underground.

Why the dark head matters

The very dark head may be the most important part. Inland taipans spend much of the day in deep cracks in the clay soil and in old rat burrows. On a cool morning, a snake can push just its head out of the entrance into the sun. A black head absorbs heat fast, and the warmed blood then carries that heat to the rest of the body while most of the snake stays hidden and safe.

This lets the snake reach a working temperature quickly and spend less time exposed. Inland taipans are mostly active in the early morning, when they bask briefly and hunt near burrows before retreating for the rest of the day. Warming up fast makes that short window more useful. In cooler weather they may also come out in the afternoon, and road-killed snakes found in winter show that they stay active then too.

How reptiles change color

Reptiles change color in two main ways, which biologists call physiological and morphological color change.

Physiological color change is fast. Special pigment cells in the skin, called melanophores, contain the dark pigment melanin. When the melanin spreads out through the cell, the skin looks darker; when it gathers into a small dot, the skin looks paler. Chameleons, anoles and the central bearded dragon of Australia use changes like this, along with other cell types, to shift shade within minutes. Bearded dragons, for example, are darker when cold and lighter when warm.

Morphological color change is slow. It involves a change in the amount of pigment or in the number of pigment cells, built up over days, weeks or months. Seasonal changes, such as the inland taipan’s, are generally of this slower kind. Exactly how the inland taipan’s change works at the level of its skin cells has not been studied in detail.

This is different from the dull, bluish look many snakes have just before they shed their skin. That short-term change comes from fluid building up between the old and new layers of skin, and it disappears as soon as the snake sheds.

Does the color help with camouflage?

Color may also help the inland taipan blend in, although this is less certain. The cracking-clay floodplains and gibber plains where it lives range from pale sandy tones to dark brown and reddish soil, and the pale summer shade matches dry, sun-bleached ground well. However, the snake relies mostly on hiding underground rather than on camouflage in the open, so temperature control is considered the main reason for the change.

Its color has nothing to do with warning predators. Unlike the brightly ringed coral snakes of the Americas, the inland taipan has no bright warning colors. Its main defense is to slip away into a crack, and only if cornered does it raise its body in a warning display, as explained in is the inland taipan aggressive?

Other animals that change color with the seasons

Seasonal color change is rare in snakes, but common in some other animals that face strong seasonal changes. In the Arctic and in mountains, animals such as the Arctic fox, the stoat and the mountain hare turn white in winter for camouflage in snow, and brown in summer. Their change is about hiding, while the inland taipan’s is thought to be mainly about heat.

Fast color change is a different skill altogether. Cuttlefish and octopuses can change color in a fraction of a second using muscles that open and close pigment sacs in their skin. Read more in how do cuttlefish change color?

The inland taipan is better known for its venom than for its color, and you can read how it ranks in is the inland taipan the most venomous snake?