Lecture 15 Flashcards
How does the body mass of male emperor penguins change in the first 75 days of fasting?
There is a steady state of mass loss until you get to about 75 days
What does it mean if protein metabolism is occurring?
Starvation is occurring because they are having to metabolise their tissues
What are corticosterone hormone?
Is a stress hormone
What could be a trigger for male emperor penguins to abandon their egg or chick?
Corticosterone hormone
At about what weight do male emperor penguins abandon their egg or chick and return to the seas? When is this also the case?
At about 25 kilo.
When done in a lab this is when they try to get out of their pen
(So at this point they will have just enough reserves to make the trek to the sea to start feeding again)
When male emperor penguins are fasting/ reading the egg or chick they are fairly quiescent (don’t move around very much) however, when does this change?
They do this until they get to about the 25 kilo stage
How many eggs do female Eider ducks lay? And what does she do once she has laid them?
About 10-15 eggs.
Then she sits on them and doesn’t move until they hatch and when they hatch she takes them all down to the sea where she starts feeding
(Doesn’t feed but she does get off the nest)
Female eider sucks fast once they have laid their eggs and sit on them until they hatch. How long does this usually take (so how long does she fast for)?
Takes about 25 days
How do we know that when Eider ducks get off the nest, wonder around, may even go in the water and then come back to the nest that they don’t feed?
Because their body mass stays the same
When do Eider ducks get off the nest more frequently and the duration in which they get off the nest increases and she starts feeding?
When it gets over 25/ 26 days and the chicks haven’t hatched
What is the issue when female Eider ducks begin to get off their nests more frequently for increased durations of time when the chicks haven’t hatched (so when it is over 25/ 26 days)?
It is not good for the chicks because they are not being incubated and they are exposed to predators
What triggers Eider ducks to get off their nests when it is over 25/26 days and the chicks haven’t hatched?
Is related to corticosterone levels and when the fat reserves have run out and the protein is starting to be utilised.
(Doesn’t happen with all of them and there are many occasions where the females are found dead on the nest)
When do animals go into the starvation period?
When they have used up all the fat and they are having to rely on the protein of the tissues
What happens in the phase 1 of fasting? (What is it related to, why for this long etc.)
Rapid body mass change in the first few days is related to them utilising all their carbohydrates reserves which they don’t have a lot of because fat is the best/ energy dense, 10 times the energetic density
What is the rapid change is body mass in phase 1 of fasting related to?
It is because carbohydrates are stored in their hydrated form the rapid change in body mass is related to the water being lost as well
What are the benefits of huddling?
. Reduces heat loss
. Warms the local environment
Give an example of an animal that huddles
Golden snub-nosed monkeys
Give an example of where huddling would warm the local environment
A hole in a tree, then the group of warm bodies will warm the local environment so reduce the temp difference and therefore keep your temp up
Why does huddling reduce heat loss?
Because you are essentially becoming one giant organism and the bigger you are the slower you lose heat because less SA
Give an example of a bird species that has changed its migratory pathways in our lifetime
Blackcaps- example of natural selection and evolution process
Describe emperor penguins interaction between each other
They sit in their nests and the next animal is just outside peck range because they are very territorial. Can get roads going through so individuals can get to their nests. Unlike all the penguin species that don’t huddle in adult stage emperor penguins have changed their biology because it huddled. They take their turns to stay inside, the ones of the outside move together, exposing another one/ constant movement. So had got away from the usual penguin instincts of being very territorial and work cooperatively to form these huddles
How long do emperor penguins have to incubate their egg and raise the chick to the point when the female comes for it to be successful?
Takes about 120 days
When they studied emperor penguins that were solitary, exposed to the wind and temps and they looked at the rate of mass loss how long did they estimate that it could last? So what does this mean?
50-60 days.
So this means they would abandon the egg/ chick because it doesn’t have the resources to survive
They kept some emperor penguins inside so that they were exposed to the temp but not to the wind and what did they find?
That the rate of the mass loss was about 60-70 days and was predicted that they would abandon the egg/ chick
