Humpback Flashcards
Humpback length
40-50ft, females longer, reverse sexual dimorphism
Weight
60,000-90,000lb or 30-45 tons
Tail width
13-18ft
Pectoral flipper length
13-16ft
Length at birth
12-15ft
Weight at birth
1,500-2,000lb
Lifespan
70-100years
Sexual maturity
6-8years
Diet
Krill small fish herring
Number population segments
14
How many whales in 1966
1,500-2,000 in central n pacific
How many whales now
20,000+ in central n pacific
How long is total yearly migration
6,000
Why cold water in summer
Warm waters do not hold onto dissolved oxygen as well so are not as productive / there isn’t as much food there
How much body weight can humpbacks lose in summer
Up to 1/3
Why do they leave Ak for winter
Avoiding predator species of transient orcas
What is the survival rate for 1st year of humpback life
70%
What is baleen made of
Keratin
How many baleen plates
400
How big is humpback throat
15in - about the size of grapefruit
What is a temporary whale gathering called
Gam
How long is a typical dive
5-7mins
How long can humpbacks hold breath
Almost an hour
Record humpback depth dive
2,021 ft
Avg humpback dive depth
700ft
How is humpback skeletal structure adapted to diving
Tiny and irrelevant sternum gives ribs extra flexibility along w angle and flexible jointer –> lets them collapse lungs on a deep dive
Explain whale sleeping
Whales are conscious breathers –> voluntary breath at surface, hemispheric resting lets them stay partly conscious and have 1/2 of brain asleep at time for periods of 15-40 mins and 2-5hrs per day –> behavior called logging
How long is gestation period
11-12months fitting w migration timeline
How often do they reproduce
2-4yrs
What percent milk fat is mothers milk
50% (human is 3-4%)
How much milk consumed per day
Over 100 gallons gaining 80-100lb per day
Primary threats
Ship strikes and entanglement in fishing gear, also acoustic disturbance, climate change, stress from rec vessels and ocean debris
