Dolphins

Question 1

average size of dolphins

Answer 1

between 9-20 feet

Question 2

locations of dolphin habitats

Answer 2

inshore, offshore, coastal

Question 3

describe the head of a dolphin

Answer 3

bulbous melon on head with a protruding distinctive beak

Question 4

describe the teeth of a dolphin

Answer 4

conical (cone) shaped teeth

Question 5

life span of dolphins

Answer 5

about 40 years

Question 6

how many species of dolphins are there

Answer 6

38 oceanic species and 4 endangered river species

Question 7

largest species of dolphin

Answer 7

orca

Question 8

list 4 endangered river dolphin species

Answer 8

amazon river dolphin, ganges river dolphin, indus river dolphin, and irrawady dolphin

Question 9

what species of dolphin is blind

Answer 9

indus river dolphin

Question 10

list 30 species of dolphins

Answer 10

1. atlantic bottlenose dolphin
2. pantropical spotted dolphin
3. commerson’s dolphin
4. hector’s dolphin
5. dusky dolphin
6. short beaked common dolphin
7. atlantic spotted dolphin
8. orca
9. clymene dolphin (short snouted spinner dolphin)
10. fraser’s dolphin
11. paele’s dolphin
12. southern right whale dolphin
13. indo-pacific bottlenose dolphin
14. false killer whale
15. atlantic white-sided dolphin
16. atlantic humpback dolphin
17. long-beaked common dolphin
18. long-finned pilot whale
19. melon headed whale
20. pygmy killer whale
21. northern right whale dolphin
22. pacific white sided dolphin
23. risso’s dolphin
24. rough toothed dolphin
25. short beaked common dolphin
26. short finned pilot whale
27. spinner dolphin
28. striped dolphin
29. taiwanese humpback dolphin
30. white beaked dolphin

Question 11

smallest species of dolphin

Answer 11

hector’s dolphin

Question 12

what is the average size of the world’s smallest dolphin (hector’s)

Answer 12

4-5 feet

Question 13

where is the largest concentration of bottlenose dolphins found

Answer 13

gulf of mexico

Question 14

global population of bottlenose dolphins

Answer 14

600,00

Question 15

where are bottlenose dolphins found

Answer 15

• Along the West Coast off California, Oregon, and Washington, in the Hawaiian islands, along the East Coast from Massachusetts to Florida, throughout the Gulf of Mexico, and in the Caribbean
• Temperate and tropical waters around the world
• Inhabit a wide variety of habitats, including harbors, bays, gulfs, and estuaries, as well as nearshore coastal waters, deeper waters over the continental shelf, and even far offshore in the open ocean

Question 16

do bottlenose dolphins present sexual dimorphism

Answer 16

no

Question 17

differences between male and female bottlenose genitalia

Answer 17

males: exclamation point, internal examination of male will allow for you to only slide finger backward
females: divide, internal examination will allow for you to slide finger forward

Question 18

describe genitalia of female cetaceans

Answer 18

vagina and anus are both contained within one external genital slit with mammary slits flanking the genital slit forming a division symbol

Question 19

average length/weight of adult bottlenose dolphin

Answer 19

7 to 9 feet (some reach 13 feet) and 400 to 600 pounds (some reach 1,300 pounds)

Question 20

lifespan of bottlenose dolphin

Answer 20

about 40 years (some [females mainly] live up to 60 years)

Question 21

when do bottlenose dolphins reach sexual maturity

Answer 21

females: 5 to 10 years
males: 8 to 13 years

Question 22

gestation period of bottlenoses

Answer 22

12 months

Question 23

how often do female bottlenoses produce a calf

Answer 23

every 3 to 6 years

Question 24

how often do female bottlenoses ovulate

Answer 24

up to 7 times per year and the ovulation cycle can last up to a month

Question 25

fission-fusion of bottlenose dolphin pods

Answer 25

group composition of bottlenose pods changes; individuals associate in groups dynamically. They merge or split within the same aggregation several times per day.

Question 26

average size of dolphin pod

Answer 26

2 to 15 individuals but super pods have been observed with over 100 (sometimes 1,000) dolphins

Question 27

superpods are common amongst which species

Answer 27

orcas, bottlenoses, and risso's dolphin

Question 28

how many sets of teeth do dolphins possess

Answer 28

one set (monophydont)

Question 29

how many teeth do bottlenose dolphins have

Answer 29

86 to 100 teeth

Question 30

which dolphin species has the most teeth

Answer 30

long beaked common dolphin (240 teeth)

Question 31

which dolphin species has the fewest teeth

Answer 31

risso's dolphin (4 to 14 teeth)

Question 32

how many teeth do orcas possess

Answer 32

40 to 56 teeth

Question 33

why do dolphins possess a gap between their teeth at the front of their mouths

Answer 33

allows the baby to latch on to the mother's nipple without biting her

Question 34

average thickness of dolphin blubber

Answer 34

3/4 inches to 1 1/4 inches thick (thickness related to type of environment)

Question 35

what is blubber

Answer 35

modified third layer of hypodermis

Question 36

how many layers of skin do dolphins possess

Answer 36

3 layers

Question 37

list the 3 layers of dolphin skin

Answer 37

epidermis (top layer), dermis (middle layer), hypodermis (bottom layer)

Question 38

how thick is the epidermis of dolphins compared to land mammals

Answer 38

ten times thicker

Question 39

how often does the epidermis of a dolphin shed/slough off

Answer 39

every two to four hours (keeps the dolphin streamlined and moist)

Question 40

mammal classification

Answer 40

hair or fur, warm blooded, live birth, milk fed via mother's mammary glands, well developed brain

Question 41

how are dolphins classified as mammals

Answer 41

dolphins possess one quarter inch long whiskers on their rostrum that will fall out shortly after birth as a result of the water pressure

Question 42

which cetaceans retain their whiskers after birth

Answer 42

some great whales and one type of river dolphin

Question 43

are bottlenose dolphins endangered

Answer 43

No

Question 44

how far can dolphins see above water

Answer 44

between 12 to 18 feet

Question 45

how well can dolphins see underwater

Answer 45

about 9 feet

Question 46

how do dolphins possess "night vision"

Answer 46

blue/green tissue called the tapetum lucidum gathers all available light and reflects it back through the lens allowing for better vision dogs and cats possess this as well

Question 47

do dolphins possess a nictating membrane

Answer 47

no, they possess external upper and lower eyelids

Question 48

which possess larger bone surface and subsequently more extensive muscle: odontocetes or mysticetes

Answer 48

odontocetes as they require larger muscle mass for hunting prey

Question 49

how many beats per minute occur when a dolphin is diving

Answer 49

drops to about 12 beats per minute to conserve oxygen

Question 50

how many beats per minute occur when a dolphin is surfacing

Answer 50

rises to about 100 to 120 beats per minute

Question 51

how long can a dolphin hold its breath for

Answer 51

10 minutes is average (bottlenoses have been recorded at 20 minutes) deep diving offshore species such as risso's dolphin can hold its breath for 30 minutes

Question 52

what causes offshore dolphin species to have darker muscle color

Answer 52

increased myoglobin due to deep diving and increased need for oxygen

Question 53

how is the increase in BPM in dolphins managed when they surface

Answer 53

retia mirabilia (tissue containing dense mass of blood vessels that controls the flow of blood to the dolphin's brain)

Question 54

why is there a range when sexual maturity occurs in bottlenose dolphins

Answer 54

exact age varies between populations

Question 55

how long do bottlenose calves nurse off mother

Answer 55

20 months