Pink pygmy seahorse hidden among sea fan coral

The pygmy seahorse, Hippocampus bargibanti, matches the colour of its coral home © Chanwit Polpakdee/Shutterstock.com

Rainbow nature: life in proud pink

While we humans associate pink with romantic roses and blushes, pink in the natural world can be a warning or part of an elaborate disguise.

Discover nine examples of proud pink wildlife below.

Lesser flamingos wading in Lake Nakuru, Kenya

The flamingo's shade of pink depends on the levels of carotenoid pigments in its diet. Caribbean flamingos display redder hues than their Kenyan counterparts. © Paul Mannix, licensed under CC BY 2.0
 

Flamingo (Phoenicopteridae family)

If you're a flamingo, you really are what you eat: the colour comes from a diet of shrimp and microalgae, in particular diatoms and blue-green algae. Flamingo chicks are grey. They gradually gain their pink hue as they moult and grow new feathers.

The algae contain pigments called carotenoids, the same pigments that give tomatoes and carrots their vivid colours. Shrimps eat the algae and flamingos eat both, meaning the birds accumulate large amounts of carotenoids.

Flamingos' livers break down the carotenoids, and the molecules are then absorbed in fats deposited in the birds' feathers, bills and legs.

Humans also eat foods containing carotenoids. If eaten in high enough quantities this can cause a condition called carotenoderma - an orange tinge to the skin.

The bright pink millipede Desmoxytes purpurosea on a cave wall

This beauty was number three on the International Institute for Species Exploration's Top 10 New Species list in 2008 © Jung Hsuan/Shutterstock.com
 

Shocking pink dragon millipede (Desmoxytes purpurosea)

This millipede is shocking by name and by nature - it produces deadly hydrogen cyanide from its defensive glands, a trait that also gives it a distinctive almond smell.

The species was first described in 2007 from specimens found in a unique habitat in Thailand - the Hup Pa Tard limestone cavern.

This high-humidity location is thought to be an ancient cave system with a collapsed roof, leaving steep mountain sides.

The enclosed valley hosts lush tropical vegetation and several rare species such as the Siamese fireback pheasant and one member of a goat-like group of creatures called serows.

An axolotyl with pale pink skin, dark black and pink gills, and black eyes

Axolotls that look pink are missing cells containing the brown pigment melanin from most of their body © Amandasofiarana, licensed under CC BY-SA 4.0 via Wikimedia Commons
 

Axolotl or Mexican salamander (Ambystoma mexicanum)

Axolotls are amphibians, but in the wild most individuals don't go through metamorphosis. This means that if they were frogs (another amphibian) they would never get beyond the tadpole stage. Axolotls keep their distinctive feather-like gills into adulthood and live underwater.

They can be induced into metamorphosis, however, by the addition of iodine, an element lacking in their native habitat. They also have a remarkable ability to regrow limbs.

Axolotls are listed as critically endangered in the wild, and are known only from one area in Mexico. There were 100 individuals per square kilometre in 2008, but a 2013 search found no individuals in their native habitat.

Pink hydrangea flower

The flowers of some species of hydrangea, such as Hydrangea macrophylla, change colour in different soils © DonBanana, licensed under CC BY-SA 3.0 via Wikimedia Commons
 

Hydrangea

This large group of flowering plants originated in Asia and the Americas.

The flowers of hydrangeas are usually white, but some species can display a variety of pink, red, purple and blue hues. Their individual colour depends on the chemistry of the soil, earning them the nickname 'change rose'.

For species such as H. macrophylla and H. serrata, an alkaline soil (above pH 7) will result in pink or red flowers. This is because aluminium ions in the soil are less available to the plant than they would be under acidic conditions. At a lower pH (below 7), the plant takes up more aluminium ions and the flowers are blue. 

Elephant hawkmoth resting on a branch

This exotic-looking moth, Deilephila elpenor, is a common inhabitant of the UK © Hamon jp, licensed under CC BY-SA 3.0 via Wikimedia Commons
 

Elephant hawkmoth (Deilephila elpenor) and small elephant hawkmoth (Deilephila porcellus)

Elephant hawkmoths have the rare distinction of being named after a mammal, a bird and an insect.

These pretty moths are found throughout the UK, although because they fly at night and rest during the day, their vivid pink and olive colours go unseen by many people. The slightly smaller Deilephila porcellus is the more brightly coloured of the two.

The caterpillars of these moths are also very obvious. They have distinctive eye markings and a rather fat body, and fancifully resemble an elephant's trunk - hence the name.

Hawkmoths are characterised by their ability for rapid, sustained flight, with some species able to hover while extracting nectar from flowers.

Brightly coloured Liophidium pattoni in Madagascar, showing the pink pattern on its black body

Liophidium pattoni preys on small lizards on the forest floor © Bernard Dupont, licensed under CC BY-SA 2.0
 

Liophidium pattoni

With bright pink and blue flecks and a yellow underside that's pink at the tip, this colourful snake was first described in 2010.

It is one of more than 615 new animal and plant species described in Madagascar between 1999 and 2010.

Despite its relatively recent scientific discovery, the population of Liophidium pattoni is already thought to be decreasing due to destruction of its forest habitat.

Madagascar is home to approximately 90 species of snakes, but the majority are dull in appearance. L. pattoni is neither venomous nor aggressive, so its markings may be a ruse to mimic bad-tasting millipedes and put off predators.

Naked mole rat emerging from a tube

Naked mole rats are the longest-living rodents, with a lifespan of over 28 years © belizar/Shutterstock.com
 

Naked mole rat (Heterocephalus glaber)

Many mammals are born hairless and wrinkly, but naked mole rats stay that way. Despite their undeniable ugliness, they are remarkable creatures.

Naked mole rats burrow underground in hot, dry parts of East Africa, surviving in colonies of up to 300 individuals. They are possibly the only example of eusocial behaviour in mammals - the colony is arranged so that only one female produces young, just like in a bee or ant colony.

Naked mole rats also have some physical features that make them unique among mammals and particularly interesting for research, including a remarkable resistance to cancer and some types of pain.

Two pink and grey-coloured pygmy seahorses on coral

As the name suggests, pygmy seahorses are one of the smallest seahorse species, reaching only around two centimetres in length © Todja/Shutterstock.com
 

Pygmy seahorse (Hippocampus bargibanti)

Pygmy seahorses are so well camouflaged against their preferred coral habitat that they were only discovered when a branch of coral was under examination in the lab.

Given this ability, it's no surprise that their conservation status is listed as 'data deficient - meaning scientists don't know enough about their population to make an assessment.

These tiny seahorses vary in colour from yellow and orange to pink and grey, matching the type of sea fan coral they come to rest on as an infant.

A pink bush-cricket

Bush-crickets, also known as katydids, are related to grasshoppers and crickets © Flickr user Ric McArthur, licensed under CC BY 2.0 via Wikimedia Commons
 

Oblong-winged bush-cricket (Amblycorypha oblongifolia)

This insect is usually bright green, but every so often a pink one will turn up. For many decades, entomologists thought these insects were rare 'mutants', carrying a similar genetic aberration to the one that causes albinism - a condition that robs creatures of their normal pigments, leaving them white (and pink where blood vessels are visible).

It is now widely accepted that pink bush-crickets' hue is the result of a condition called erythrism, with genetic mutation causing an absence of the usual pigment and overproduction of another.

However, recent breeding experiments suggest that the pink colour may actually be the dominant genetic condition for these bush-crickets. Despite this, green individuals remain far more common in the wild thanks to the survival advantage the colour green gives insects that live among leaves.