Dolpin (12) Flashcards
What is the largest dolphin species?
The orca, also known as the killer whale.
What is the maximum weight of an adult orca?
5,400 kilograms
- What is the smallest porpoise species?
- What other accolade does it hold?
- The vaquita, an incredibly stupid looking animal.
- It’s also one of the most endangered marine mammals on Earth.
What physical feature helps distinguish dolphins from porpoises?
Dolphins have prominent beaks; porpoises have rounded heads.
What shape are dolphins’ dorsal fins?
Curved and hook-shaped.
What shape are porpoises’ dorsal fins?
Triangular.
How do the teeth of dolphins differ from those of porpoises?
Dolphins’ teeth are pointed and cone-shaped; porpoises have spade-shaped teeth.
Are dolphins or porpoises generally longer and leaner?
Dolphins are generally longer and leaner than porpoises.
Which group of animals is thought to be less social, dolphins or porpoises?
Porpoises are thought to be less social than dolphins.
Do porpoises engage in blowhole whistling communication?
Scientists believe porpoises do not engage in this behaviour.
What is a possible reason porpoises do not whistle?
Structural differences in their blowholes.
Which species is more likely to approach boats, dolphins or porpoises?
Dolphins are more likely to approach boats.
What is the typical depth range for bottlenose dolphins when they’re inshore?
Less than 50m deep
What factors can segregate different bottlebose dolphin populations in the English Channel (2 Points)?
Genetic and social factors
Bottlenose dolphins tend to have strikingly limited _______.
Ranges
What can the four English Channel bottlenose dolphin ecotype groups be separated into?
Pelagic ecotype (found in shelf waters) and coastal ecotype
What type of populations do coastal ecotype bottlenose dolphins typically form?
The coastal ecotype forms small, discrete, and separate coastal populations.
True or False: The pelagic ecotype of bottlenose dolphins is found in small, discrete populations.
False - the pelagic ecotype occurs in large numbers, unlike the coastal ecotype.
What significant change in ambient noise levels did Ross estimate between 1950 and 1975?
An increase of 10 dB in areas where shipping noise dominates
The more powerful the engine of a vessel, the greater the amount of _______ it will produce.
sound (at least at low frequencies)
- What are the two main types of sounds produced by toothed whales and dolphins (so not whales)?
- What is each one mainly used for?
- Pure tone whistles (500 Hz - 20 kHz)
- Pulsed sounds or clicks (500 Hz - 150 kHz)
Pure tone whistles are mainly used for communication, while pulsed sounds are primarily for echolocation.
What is the frequency range of pure tone whistles produced by toothed whales and dolphins (not whales)?
500 Hz - 20 kHz
These whistles are primarily used for communication.
What is the frequency range of pulsed sounds or clicks produced by toothed whales and dolphins (not whales)?
500 Hz - 150 kHz
These sounds are mainly used for echolocation.
What is the preferred habitat of humpbacks?
Waters over and along the edges of continental shelves and around some oceanic islands
Where do humpbacks mate and give birth?
Over shallow banks in tropical waters
When do humpback births peak in the North Atlantic?
February on Silver Bank in the Caribbean (a submerged carbonate plateau in the Caribbean Sea)
What is the typical social structure of humpbacks?
Usually seen singly or in pairs, groups rarely exceed 4-5 animals unless in feeding or breeding aggregations
Which zooplankton is mainly consumed by humpbacks?
Euphausiids (krill)
What factors influence the localities of humpbacks in summer?
Local prey availability
True or False: Humpbacks are primarily found in polar regions.
False - while they do take euphausiids in greater quantities in polar regions, they are not primarily found there.
