Diet Compensates for Mineral Deficiencies

Biological Strategy

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Capture, Absorb, or Filter Chemical Entities

Living systems often require chemical elements and chemical compounds, including complex sugars, proteins, and odor-making compounds, to perform critical activities. These compounds exist in various states–solid, liquid, and gas–and are ubiquitous in soil, water, and air. This requires that living systems not only have ways to capture, absorb, or filter them, but also ways to differentiate among them, selecting those that are valuable or harmful. For example, mangrove trees live with their roots in salty water and sediments. Various mangrove species have different strategies for removing salt from the water they take in so that their tissues can use the fresh water.

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The environment is constantly changing, and if living systems can’t adapt to these changes, they don’t survive. Environmental changes can be cyclic such as seasons, sudden such as floods or forest fires, or gradual but long-term, such as ecosystems shifting from early to mature stages. These changes require some flexibility in behavioral responses to match the specific conditions. For example, as a fish called the lamprey swims, it constantly faces changes in currents. Skin sensors help it detect those changes and adjust its motion accordingly.

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Mammals

Class Mammalia (“breast”): Bats, cats, whales, horses, humans

Mammals make up less than 1% of all animals on earth, but they include some of the most well-known species. We know first-hand some of the characteristics that make mammals unique, like having hair, being able to sweat, and producing milk through mammary glands. Another critical shared feature is a set of highly-specialized teeth. Unlike sharks or alligators, for example, whose teeth are generally all the same size and shape, mammals have differently shaped teeth in different areas of the jaws to target specific foods or foraging strategies.

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The dietary behavior of some red deer compensates for periods of mineral deficiencies by eating bones of small birds.

Image: Mehmet Karatay / Wikimedia commons /

Red deer stag (Cervus elaphus) with velvet antlers in Glen Torridon, Scotland

Image: Luc Viatour / Wikimedia Commons /

A Red deer (Cervus elaphus), in Freyr forest, near Han-sur-Lesse, Belgium.

“On one of Scotland’s western outposts, the island of Rhum in the Inner Hebrides, there are more than 300 red deer (Cervus elaphus). Although they are the same species as those found on the Scottish mainland, the red deer of Rhum exhibit a macabre dietary deviation that sets them far apart from others of their species.

“These ostensibly mild-mannered herbivores have acquired a murderous interest in the chicks belonging to the large population of Manx shearwaters (Puffinus puffinus) that nest on the ground around this island. Quite simply, the deer frequently bite off the heads of these unfortunate young birds in order to chew their bones. A detailed study, conducted by Glasgow University zoologist Dr. Robert Furness, confirmed the behavior and his findings were reported in 1988.

“The reason for this bizarre activity appears to be that Rhum, which is only a small island, is deficient in certain minerals – in particular calcium and phosphorus – that the deer require to sustain their dietary balance and metabolism. Elsewhere, deer circumvent this problem by chewing their own shed antlers, or even the bones of dead deer. On Rhum, however, which is amply supplied with defenseless shearwater chicks that make easy prey, the red deer have become carnivorous. They kill the birds to supply themselves with bony material to chew on and are therefore able to obtain the minerals they require.” (Shuker 2001:118)

Last Updated August 18, 2016

References

Book

The Hidden Powers of Animals: Uncovering the Secrets of Nature

26/02/2021 | Dr. Karl P. N. Shuker

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