Lecture 15- Monotremes II (echidna) Flashcards Preview

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How many species of echidna are there?

-long beaked echidna (2 species but poorly described, lives in PNG)
-short beaked echidna, widespread (Australia and PNG)


How much does an echidna weigh?

-up to 6.5 kg


How long can echidnas live for?

-long lived
-up to 45 years, average about 17


When are echidnas active?

-diurnal but flexible (anti predator behaviour and avoidance of extreme heatú


How do echidnas react when they see a predator?

-digging claws to dig in the ground
-dig themselves so only the spines visible and exposed= predator avoidance mechanism
-moves slowly due to reptilian pectoral girdle= but smart like cats


Where does the short beaked echidna live?

-whole of Australia and PNG (even the deserts etc= ants are everywhere)
-most widely distributed mammal in Australia


What sort of habitats do echidnas occupy?

-huge range
-hot arid areas to alpine areas
-it is possible that there may be some variation in thermal ecology and energy needs in echidnas living in such different environments


How do echidnas maintain stable body temperature?

-via thermogenesis (heat production via metabolic activity)


What does heterothermic mean?

-some endotherms are heterotherms
-exhibit marked changes in Tb(body temp): torpor/hibernation


What is hypothermia?

-decline in body temperature below the narrow range normally maintained by a particular endothermic species, need to be warmed up by outside sources to get out of this


What is natural hypothermia?

-animal able to re-warm spontaneously via thermogenesis


What is the pattern for torpor/hibernation for mammals and birds?

-large drop in body temp and a reduction in metabolic rate (reflected in decrease use of O2) thus a reduction in energy use


Does duration of torpor/hibernation vary?

-yes, vary across species
-some species go into torpor every day


What is the temperature of active echidna?

-during summer


What happens to an echidna in winter?

-bouts of torpor
-lowers temp tas much as to 5C
-when in hibernation cannot move
-must be in a safe place so it doesn't get predated


When do echidnas go into torpor?

-some go into torpor before winter, at a time when fattest
-some animals didn't go into torpor=when not fat enough and juveniles
-even in desert go into sort of torpor when food shortage


What is the function of torpor in echidnas?

-inhabit low productivity environments, some cold, some arid= food shortages common
-torpor= an energy saving strategy to deal with periods of low energy availability


How is echidna feeding ecology determined?

-faecal analysis


What is a myrmecophage?

-specialised in eating social insects (ants, termites) more than 75% of diet
-ants and termites high in fat compared to many other invertebrates
-echidnas are myrmecophages


What are some common characteristics of myrmecophages?

-very reduced or no teeth
-long narrow snout
-sticky tongue
-(eg. echidna, aarvark)


WHat was the result of the study looking at diet in echidnas?

-30% ants
-70% larvae and pupae= coleoptera= big larvae= smash them with their tongue and suck the contents out

-so there is variation from environment to environment in what they eat


WHat is the diet of echidnas?

-preference for ants, but some flexibility
-seasonal changes related to prey availability
-scrab beetle larvae (20-40% fat) important seasonall. Intake correlates with energy demands.
-maybe use electro-reception(nose poke and hold) when foraging in soil


When do echidnas breed?

-seasonal breeders
-males form trains (follow females)=the first male= the highest level of testosterone


How long is gestation?

23 days


How many eggs?

1 egg laid into pouch
(1 young /1 year)


How long is incubation?

10 days


Where are the young in the beginning of their life?

-carried in pouch for 45-55 days then left in nest/burrow (get spikey then)= risk of predation at this stage


How long does lactation last?

-6 months