BBC Wildlife - UK (2020-04)

STUARTBLACKMAN

Sciencewriter

Newt: Remi Masson/naturepl.com; nightjar: Nature Photographers Ltd/A

amy;

orangutan:

Edw

nG

esbers/naturep

.com

T

here’sa worldofdifferencebetween

a deepsleepandhibernationproper.

Duringcoldorwetweather,parent

swiftsfindit hardtocatchenough

airborneinsects,sotheirchicksback

at thenestchillthemselves,reducing

theirmetabolismtogowithoutfoodfor

48 hours– enoughtosurviveuntilthe

frontpasses.Butthisis semi-torpor,not

hibernation.Manynormallyhyperactive

hummingbirdsdosomethingsimilar,

enteringa stateofsuspendedanimation.

Theirmetabolismslowsright

down,theirbreathhardly

detectable.Again,however,

thisis anexampleoftorpor.

Justonebirdis knowntobea true

hibernator:NorthAmerica’s

commonpoorwill.This

beautifullycamouflagednocturnalbirdis

a relativeofthenightjarfoundinBritain,

andinwinteroftenhibernatesamong

rocks.It canslashitsoxygenintake

by 90 percent,whileitsbody

temperatureplummetsto

5°C,barelyregistering

signsoflife.

BenHoare

Dobirdshibernate?

BEHAVIOUR

Q&A

A bird that’s up all night,

the common poorwill

can be a particularly

heavy sleeper.

Greatcrested

newts’ability

toregenerate

lessensas

theyage.

ALIXHARVEY

MarineBiologicalAssociation

ELLENHUSAIN

Wildlifefilmmaker

80 BBC Wildlife

Thismonth’spanel

LAURIEJACKSON

Wildlifetourleader

HELENPILCHER

Sciencewriter

LIZKALAUGHER

Sciencewriter

RICHARD JONES

Entomologist

A

utotomy, also known as self-

amputation, is a somewhat

counterintuitive but potentially

life-saving behaviour, which has

evolved in numerous animal

groups. This last-ditch defence

against predators is used by

many invertebrates, as well as

by some mammals, amphibians

and reptiles. But while shedding

a body part is one thing, being

able to regenerate it is another one

altogether. Salamanders and newts

are unique among vertebrates in

their ability to regenerate missing

parts, including the limbs, eyes

and tail. Lizards can regrow a

functional tail, but it often differs

markedly in appearance and

contains cartilage rather than bone.

Meanwhile, salamanders and

newts reproduce a perfect replica.

Their

secret

involves the formation

of a blastema (a mass of cells)

containing cells capable of

differentiating into many types,

including muscle and bone cells.

The formation of the replacement

follows the growth sequence seen

during embryo development.

Laurie Jackson

Which animals can regenerate?

BIOLOGY

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