Hedgehog Awareness Week

For Hedgehog Awareness Week, Zoology Collections Manager Mark Carnall and Museum Librarian and Archivist Danielle Czerkaszyn discuss these prickly and charming creatures.

The 2-8 May is Hedgehog Awareness Week, which give us an excuse, not that one were needed, to talk about these charismatic mammals. Although the West European hedgehog (or common hedgehog if you’re in Europe, these vernacular names get very confusing when geography and language is taken into account), Erinaceus europaeus, is probably the hedgehog that springs to mind to many of our readers, there are nearly twenty living species of hedgehog and many fossil species are known.

Hedgehog specimen at OUMNH

In terms of evolutionary relationships they share a family with the moonrat and the rather wonderful gynmures, distinctly un-hedgehog-like relatives.

Their characteristic spikes that run across the back of hedgehogs are modified hairs which are periodically replaced and each individual hedgehog has around 7000 spines at any one time, varying slightly with age and size. Behaviourally, they are competent climbers (and have a built in shock-absorbing coat should they fall) and surprisingly perhaps, all species are thought to be competent swimmers.

Although much loved across their native range, Erinaceus europaeus, is considered a pest species in New Zealand where it was deliberately introduced as a form of biological control, by acclimatisation societies and possible as pet animals. They have now spread to all but the highest parts of New Zealand threatening native species of birds, amphibians, reptiles and directly competing with native mammal species.

In 2020, Erinaceus europaeus was added to the Red List for British Mammals as vulnerable across the lists for Great Britain, England, Scotland and Wales informed by analysis of citizen science data although there remains some uncertainty about true population levels.

Unsurprisingly perhaps they are comparatively well represented in the collections at the Museum including specimens donated and prepared for the Museum from the 19th Century through to much more recent specimens acquired from road death animals for display. The specimen pictured above being one such relatively recent acquisition for display in the Museum’s display case on the animals featured in Alice in Wonderland.

We’ll leave you with one more hedgehog from the Museum’s library and archives. Hedgehogs unusual appearance initially led to some odd beliefs about why their quills existed. For example, in his book ‘The History of Four-Footed Beasts and Serpents’ (1658) Edward Topsell wrote:

“The hedgehog’s meat is apple, worms and grapes: when he findeth them upon the earth, he rolleth on them until he hath fylled up all his prickles, and then carrieth them home to his den.”

– Edward Topsell

One of the most common questions about hedgehogs is how do they mate? The answer is of course, very carefully.

Uncovering ancient threads

By Dr. Frankie Dunn, Research Fellow

Some of the very oldest complex, macroscopic communities on Earth appear in the fossil record about 570 million years ago and record the presence of a group of organisms – the rangeomorphs – with an unfamiliar body plan that, at their ultimate extinction, was lost from life’s repertoire.

Rangeomorphs are characterised by a strange frondose branching anatomy, where large primary branches host smaller branches which themselves host smaller branches again. This arrangement appears to maximise the surface-area to volume ratio of the organism, rather like a lung or a gill would today.

The smallest known rangeomorphs are less than a centimetre in length, but they grew huge and the largest records indicate they could stand more than two metres tall. There is no evidence to suggest that rangeomorphs were able to move around, rather, they lived stuck to the sea floor in the deep ocean, far below the reach of light.

Despite this strange set of characters, there is growing consensus that rangeomorphs likely represent very ancient records of animal life. However, they lived at such a remote time in Earth’s history that they do not possess any direct living descendants. Given all this, it may not be a surprise to hear that we know relatively little about how these organisms made their living and came to dominate the ancient seafloors.

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The UNESCO world heritage site Mistaken Point in Newfoundland, Canada, is one of the sites on which we find exceptionally preserved rangeomorph fossils. Photo: Alex Liu.

In order to better understand them, my co-author Alex Liu and I travelled to Newfoundland, Canada to explore the rocks which host these remarkable fossils and over the past few years we have made an unexpected discovery. We found that fine filamentous threads connect rangeomorph fronds of the same species, in some cases over many meters, though they are typically between two and 40 centimetres long.

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An undescribed rangeomorph fossil with filamentous connections at the base of the frond. We find that this species of rangeomorph can be connected to each other over meters! Photo: Alex Liu. 

It is possible that these filaments were involved in clonal reproduction, like strawberry plants today, but they may have had additional functions such as sharing nutrients or providing stability in strong ocean currents.

The discovery of the filaments means that we have to reconsider how we define an individual rangeomorph, and may help us understand how rangeomorphs (seemingly) rapidly colonised deep-sea environments. Either way, some reassessment of the palaeobiology of these unique organisms is certainly required!

More information:

  • Read the full research paper here.

 

Top image: Beothukis plumosa, a rangeomorph from Newfoundland showing the intricate branching anatomy of rangeomorphs. Photo: Alex Liu.