Not Eggsactly What You Were Expecting

A Rare Group of Mammals with an Odd Feature

This is an echidna, sometimes called a spiny anteater (although it is not closely related to actual anteaters, even though their diet is similar). Specifically, it is a short-beaked echidna, Tachyglossus aculeatus. It is native to Australia and New Guinea, and one of the most widespread mammal species in the former. Thus, it is listed as a species of Least Concern. However, there are three other species of echidna only found in New Guinea, which all belong to a different genus, Zaglossus. Two of the three species in that genus are listed as Critically Endangered (the third is considered Vulnerable).

The interesting thing about echidnas is that they belong to an ancient mammalian lineage known as monotremes. The vast majority of the over 5,000 living species of mammals are placentals, which feed their gestating offspring through a connection to the mother called a placenta. Approximately 6% are marsupials, animals like opossums and kangaroos that carry their young in pouches after giving birth. The living monotremes consist of only the four species of echidna and the duck-billed platypus, Ornithorhynchus anatinus. They do not give birth to live young and instead lay eggs. Despite this, they are still considered mammals because they possess hair and lactal glands.

The two Critically Endangered echinas are the western long-beaked echidna, Zaglossus bruijni, seen below and Sir David’s long-beaked echidna, Zaglossus attenboroughi. The latter is named after the celebrated naturalist Sir David Attenborough, best known for the ‘Life series’ of natural history documentaries through the BBC. If you have never watched any of these, I highly recommend them. The film footage alone is worth it, but his commentary is also quite good.

Zaglossus attenboroughi in particular is highly vulnerable. Much like the dragonflies from three weeks ago, they are limited to a very small range. However, while the ranges of those species could be measured in a few thousand square kilometers, this echidna is found only in the forests of the Cyclops Mountains of New Guinea, in an area of less than 20 sq. km. Zaglossus bruijni in contrast has a much wider range in the western part of Indonesian New Guinea and is instead listed because of an 80% or greater population decline over the last three generations (about 45 to 50 years).

The threats to both species are similar. Habitat loss is a factor, but the primary cause of decline is due to hunting by humans. This usually requires the aid of dogs, as these species are nocturnal, difficult to locate, and occur at a naturally low density to begin with. Most hunting is part of local traditional practices and so education and collaboration is a requirement for positive conservation outcomes.

In my own personal experience, the vast majority of people do not hunt or kill Threatened species out of spite or malice. They do so because of longstanding traditions or because those species are often an excellent food source in a difficult environment. Events like the killing of ‘Cecil’ the lion grab headlines, but such occurrences are often linked with the ‘charismatic megafauna’ I have mentioned previously. Large, charismatic animals lend themselves to trophy hunting. The smaller, low-profile species that I feature in this Season are much more likely to be targeted for subsistence living, if they are harvested at all.

Zaglossus attenboroughi is also interesting because of its elusive nature. No individuals have been seen by naturalists since 1961, but recent expeditions have discovered evidence of their presence (recent burrows, tracks, and ‘nose poke’ feeding technique marks). They were considered possibly extinct for some time and is currently considered a ‘focal species’ for conservation and study by some organizations because of its evolutionary distinct nature (being one of only five living species of monotremes and the one least studied and understood).

I hope that over the last six weeks, you have been able to look at the examples of Threatened species and be able to see a step change in their situation as the categories get more severe. Many of the species face similar problems. The categories outlined by the IUCN are all about a matter of degrees. It is not sufficient to understand that a species is in trouble. It is also important to understand the sources of the problem, as well as the degree of threat.

Unfortunately, not all efforts at conservation succeed, as we will explore over the next two weeks. First, we’ll look at a species that is still around, but only in captivity (Extinct in the Wild), and then we’ll look at a species that has been completely extirpated and is now Extinct.