Lecture 15- Monotremes II (echidna) Flashcards
How many species of echidna are there?
3
- 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?
- torpor/hibernation
- 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?
32C
-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
- June-August
- 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
