1. Adaptations in Lung Structure:
- Seals possess large and highly elastic lungs compared to terrestrial mammals. Their lungs can hold a significant volume of air, allowing them to store oxygen before diving.
2. Minimizing Oxygen Consumption:
- When preparing to dive, seals can slow down their heart rate and reduce their metabolic rate. This helps them conserve oxygen during underwater activities.
3. Blood Adaptations:
- Seal's blood contains a high concentration of myoglobin, a protein that stores oxygen in muscles. This enables seals to efficiently transport and store oxygen in their muscles.
4. Slower Oxygen Consumption:
- Seal tissues are less sensitive to low oxygen levels compared to terrestrial mammals. This allows them to function longer with a reduced oxygen supply.
5. Blood Vessel Adjustments:
- Some seals can selectively restrict blood flow to certain organs during dives to conserve oxygen. Non-essential organs and organs that can tolerate low oxygen levels have reduced blood flow.
6. Nasal and Pharyngeal Adaptations:
- Seals have specialized nasal passages and pharyngeal structures that allow them to close off their airways when diving. This prevents water from entering the lungs.
7. Exhalation before Dives:
- Before submerging, seals almost completely empty their lungs by forcefully exhaling. This minimizes the air remaining in the lungs, reducing any risk of lung damage from changes in pressure underwater.
8. Oxygen Stores in Spleen:
- Seals store oxygen-rich blood in the spleen. When diving, the spleen contracts, releasing this oxygen-rich blood into the bloodstream.
These adaptations collectively enable seals to breathe efficiently and hold their breath for extended periods, allowing them to hunt and navigate underwater successfully.