Amphibians
Sagalla Caecilian
Boulengerula niedeni · also called sagalla caecilian, sagalla hills caecilian
The Sagalla caecilian is a limbless, nearly blind amphibian that spends its life tunnelling through the soil of a single Kenyan hillside. It is not a worm and not a snake — it is a caecilian, the least-known branch of the amphibian family tree — and it does two things that surprise most people: it smells its way through the dark with a pair of head tentacles, and its babies eat their mother’s skin.
Overview
The Sagalla caecilian is found only on Sagalla Hill in the Taita Hills of south-eastern Kenya, an area of about 30 km², in the moist soils of smallholder farms, hedgerows, and forest fragments. It is 25–30 cm long and pencil-thin, pinkish to purplish-grey, blunt at both ends, legless, with skin-covered vestigial eyes.
A caecilian, not a worm
Caecilians are the third group of living amphibians, alongside frogs and salamanders, with around 200 species in the wet tropics. On each side of the head, a small retractable tentacle carries chemical signals from the soil, letting the animal taste and smell its way forward.
Skin-feeding
The female grows a thick, fat-rich outer skin, and after the eggs hatch the young use special temporary teeth to peel and eat it every few days while she regrows it — a form of parental care called maternal dermatophagy.
Status
The Sagalla caecilian is Endangered (previously Critically Endangered). Non-native eucalyptus and pine plantations dry and acidify the soil it needs, and erosion on the steep slopes makes it worse. Conservation on the hill centres on replacing those plantations with native trees and helping farmers plant indigenous species along their erosion terraces — which improves the soil for the caecilian and for the farmers at the same time.
Sagalla Caecilian: common questions
What is a caecilian?
Caecilians are limbless, mostly burrowing amphibians, and they form the third major group of living amphibians alongside frogs and salamanders. Most people have never heard of them because they spend their lives underground or in leaf litter in the tropics and are rarely seen. They look superficially like large earthworms or small snakes but are neither — they have the moist, glandular skin of an amphibian, a backbone, a skull with jaws, and in many species a distinctive pair of sensory tentacles on the head. There are around 200 species, found in the wet tropics of Africa, Asia, and the Americas.
Do the young really eat their mother's skin?
Yes, in this species and a number of other caecilians. In the weeks before hatching, the mother's outer skin thickens and fills with fat and nutrients. Once the young hatch, they cluster around her and use a set of specialised, temporary teeth to scrape and peel off the top layer of this skin, which they eat. She regrows it over the next few days and the process repeats. This maternal skin-feeding, technically called dermatophagy, provides the growing young with a rich food source and is one of the more remarkable forms of parental care among amphibians.
Why is the Sagalla caecilian endangered?
Because it lives in one small place and depends on a specific kind of soil. The whole species is found only on Sagalla Hill in south-eastern Kenya. Historically much of the hill was cleared and planted with fast-growing non-native eucalyptus and pine, which dry the soil, make it more acidic, and strip away the moist, loose, organically rich earth the caecilian burrows and feeds in. Soil erosion on the steep slopes makes this worse. As the suitable soil shrinks, so does the caecilian's habitat, which is why it has been listed as Endangered, having earlier been assessed as Critically Endangered.
How do you help a burrowing animal no one can see?
Indirectly, by fixing the soil. Because the Sagalla caecilian needs deep, moist, well-structured earth, conservation on Sagalla Hill has focused on restoring that. Projects have removed blocks of eucalyptus and replaced them with native trees, promoted the planting of indigenous species along the terraces that farmers already build to control erosion, and worked with local schools and landowners so that people understand the harmless animal living in their fields. Improving the soil also benefits the farmers directly, which makes the approach easier to sustain.