Lecture 15- Monotremes II (echidna)

Question 1

How many species of echidna are there?

Answer 1

3

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

Question 2

How much does an echidna weigh?

Answer 2

-up to 6.5 kg

Question 3

How long can echidnas live for?

Answer 3

• long lived

- up to 45 years, average about 17

Question 4

When are echidnas active?

Answer 4

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

Question 5

How do echidnas react when they see a predator?

Answer 5

• 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

Question 6

Where does the short beaked echidna live?

Answer 6

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

Question 7

What sort of habitats do echidnas occupy?

Answer 7

• 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

Question 8

How do echidnas maintain stable body temperature?

Answer 8

-via thermogenesis (heat production via metabolic activity)

Question 9

What does heterothermic mean?

Answer 9

• some endotherms are heterotherms

- exhibit marked changes in Tb(body temp): torpor/hibernation

Question 10

What is hypothermia?

Answer 10

-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

Question 11

What is natural hypothermia?

Answer 11

• torpor/hibernation

- animal able to re-warm spontaneously via thermogenesis

Question 12

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

Answer 12

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

Question 13

Does duration of torpor/hibernation vary?

Answer 13

• yes, vary across species

- some species go into torpor every day

Question 14

What is the temperature of active echidna?

Answer 14

32C

-during summer

Question 15

What happens to an echidna in winter?

Answer 15

• 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

Question 16

When do echidnas go into torpor?

Answer 16

• 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

Question 17

What is the function of torpor in echidnas?

Answer 17

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

Question 18

How is echidna feeding ecology determined?

Answer 18

-faecal analysis

Question 19

What is a myrmecophage?

Answer 19

• 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

Question 20

What are some common characteristics of myrmecophages?

Answer 20

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

Question 21

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

Answer 21

• 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

Question 22

WHat is the diet of echidnas?

Answer 22

• 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

Question 23

When do echidnas breed?

Answer 23

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

Question 24

How long is gestation?

Answer 24

23 days

Question 25

How many eggs?

Answer 25

1 egg laid into pouch

1 young /1 year

Question 26

How long is incubation?

Answer 26

10 days

Question 27

Where are the young in the beginning of their life?

Answer 27

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

Question 28

How long does lactation last?

Answer 28

-6 months