Diving by marine animals
Natural dives of three seal species in the wild
Mammals have lungs to obtain air from the atmosphere and then will dive under water to hunt for their prey i.e. fish
However, mammals need the air holes in the ice to enable them to come up occasionally to grab a breath of fresh air
before re-submerging to continue looking for food
Therefore, mammals have a problem as they are air breathers (use their lungs) but once under the water there is no
further availability of oxygen as mammals do not have gills
Image shows
- tracking movement of seals around seas
- lots of time spent under water
- Each yellow line (dip)shows seal going under water
- But does not show how much time spent under water
Durations of dives by wild weddell seals
Graph shows
- How much time spent under water
- Mainly spend a short time under water 0-5 min
- In most cases, spending less than 20 min under water
- Can survive up to 60 min under water therefore, must have adapted some physiology, which enables seals to
survive long periods under water with 1 gasp of air.
Depth of divers by wild weddell seals
Graph showing the depth achieved by weddell seals
most seals dive between 0-100 m
But can dive as deep as 600 m
600 m means 40 atmospheres of pressure
These seals are doing this regularly and are exposed to huge pressures.
, Diving mammals
There is a lot of variation between diving mammals
Fur seals dive 260 m under water for about 8 min
Elephant seal can go down to 2000 m for 120 min
- Deeper depth and longer time compared to the fur seals
Sperm wales spend most of their time deep under water for 120 min
Humans (pearl dives= a person who dives for pearl oysters) dive as deep as 25 m for 3 min and then need a breath of
fresh air
Man (free diver) can dive deeper than pearl divers as deep as 250 m and for a longer period of time of 5 min
- Free divers adapt to a degree by slowing heart rate and use certain methods of swimming to use less energy.
Why is this all a problem? How long can brain survive without oxygen?
The brain cannot survive long periods without oxygen
Natural dives of three seal species in the wild
Mammals have lungs to obtain air from the atmosphere and then will dive under water to hunt for their prey i.e. fish
However, mammals need the air holes in the ice to enable them to come up occasionally to grab a breath of fresh air
before re-submerging to continue looking for food
Therefore, mammals have a problem as they are air breathers (use their lungs) but once under the water there is no
further availability of oxygen as mammals do not have gills
Image shows
- tracking movement of seals around seas
- lots of time spent under water
- Each yellow line (dip)shows seal going under water
- But does not show how much time spent under water
Durations of dives by wild weddell seals
Graph shows
- How much time spent under water
- Mainly spend a short time under water 0-5 min
- In most cases, spending less than 20 min under water
- Can survive up to 60 min under water therefore, must have adapted some physiology, which enables seals to
survive long periods under water with 1 gasp of air.
Depth of divers by wild weddell seals
Graph showing the depth achieved by weddell seals
most seals dive between 0-100 m
But can dive as deep as 600 m
600 m means 40 atmospheres of pressure
These seals are doing this regularly and are exposed to huge pressures.
, Diving mammals
There is a lot of variation between diving mammals
Fur seals dive 260 m under water for about 8 min
Elephant seal can go down to 2000 m for 120 min
- Deeper depth and longer time compared to the fur seals
Sperm wales spend most of their time deep under water for 120 min
Humans (pearl dives= a person who dives for pearl oysters) dive as deep as 25 m for 3 min and then need a breath of
fresh air
Man (free diver) can dive deeper than pearl divers as deep as 250 m and for a longer period of time of 5 min
- Free divers adapt to a degree by slowing heart rate and use certain methods of swimming to use less energy.
Why is this all a problem? How long can brain survive without oxygen?
The brain cannot survive long periods without oxygen
