PART 2: BIOLOGY & ECOLOGY
© Scubasigns
PART 2: BIOLOGY & ECOLOGY
Outline
1. Taxonomy and Classification
What type of animal is a it?
2. Distribution and Habitat
Where do they live?
3. Anatomy and Physiology
How do their bodies work?
PART 2: BIOLOGY & ECOLOGY
Outline
4. Feeding and Diet
What and how do they eat?
5. Reproduction and Life
How do they reproduce?
6.
cycle
Predators
Which animals prey on whale sharks?
2.1 TAXONOMY & CLASSIFICATION
True Sharks
The whale shark is a true shark:
• It has a skeleton made from cartilage
Lighter and more flexible than bone
• It’s skin is covered in dermal denticles
Tough , parasite repellent and hydrodynamic
• It has several rows of replaceable teeth
Teeth always sharp
2.1 TAXONOMY & CLASSIFICATION
Shark Success
•These features have made sharks successful
animals
•Appeared 220 million years before the
dinosaurs
• 440 different species of shark
A primitive six-gilled frilled shark
Smallest is lantern shark
just 17 cm long
• Can exist in many different habitats- even
fresh water!
Bull sharks and river sharks
happy in fresh water rivers
2.1 TAXONOMY & CLASSIFICATION:
Shark Orders
Carcharhiniformes Ground Sharks
Heterodontiformes Bullhead Sharks
Hexanchiformes Six gilled Sharks
Lamniformes Mackerel Sharks
Orectolobiformes Carpet Sharks
Pristiophoriformes Saw Sharks
Squaliformes Dog fish
Squatiniformes Angel Sharks
2.1 TAXONOMY & CLASSIFICATION
carpet shark features
Wobbegong
Zebra Shark
2 dorsal fins
Nurse Shark
Nostril barbells
Prominent ridges
Mouth at the front of the head
2.2. DISTRIBUTION & HABITAT
© Morgan Riley
• Whale sharks are found in tropical and warm-temperate seas
• Whale sharks live off-shore and close to land
• They can dive very deep (>1600m), tolerating temperatures as low as 3˚C
2.3 ANATOMY & PHISIOLOGY
•
•
•
•
12.85m largest measured WS.(Prob up to 18m)
Whale shark skin is 2mm thick covered with denticles
Thick (10-15cm) fatty layer under the skin
Spot pattern is believed to be unique to each shark and is used to identify individuals
2.3. ANATOMY & PHISIOLOGY:
Mouth
•The whale sharks mouth can be 1.5 m wide!
•The whale shark has 300 rows of very tiny rasp-like teeth that
have no obvious function
•Rhincodon means ‘rasp tooth’
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2.3. ANATOMY & PHISIOLOGY:
Eyes
• The eyes are situated on the side of the head to maximize line-of-sight
• Vision is probably quite poor - used for detecting movement within 3m
• Eyes roll when people get too close or exposed to camera flash
© Scubasigns
2.3. ANATOMY & PHISIOLOGY:
Spiracles
Small holes behind eyes
Function in whale sharks unknown
As with other carpet sharks they may help ventilate gills when the shark is
stationary
© Scubasigns
2.3. ANATOMY & PHISIOLOGY:
Nostrils
• Two circular nostrils widely spaced, at the front.
• Nostril ‘Barbells’ similar to Nurse Shark but smaller.
• Sensitive to dissolved chemicals which can help them locate prey.
© Scubasigns
2.3. ANATOMY & PHISIOLOGY:
Gills
The gills of whale sharks
function to extract oxygen and
to filter prey from seawater.
2.3. ANATOMY & PHISIOLOGY:
Other Whale Shark senses
• Hearing: Largest inner-ear in the
animal kingdom. Probably good for
low frequency sounds
• Lateral Line and Electro-receptors:
Unstudied but may have structures
other sharks use to detect vibrations
and electronic currents
2.4. DIET & FEEDING
Prey
• Whale sharks feed on tiny prey (>0.5mm)
including plankton, eggs and small shoaling
baitfish
2.4 DIET & FEEDING
Ram Filter Feeding
Whale sharks are constantly diving and
ascending - possibly in search of food
They utilise ‘ram filter feeding’…
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2.4 DIET & FEEDING
Suction Filter Feeding
…or ‘Suction’ filter feeding
•Suction filter feeding enables WS to feed on
more mobile prey
• Because WS seek high densities of prey they
are often seasonal visitors to specific locations
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2.4 DIET & FEEDING
Other filter feeders
• There are two other filter feeding sharks:
The Basking shark…
2.4 DIET & FEEDING
Other filter feeders
… and the Megamouth shark
2.5 REPRODUCTION & LIFECYCLE
• Male sharks use claspers to deposit sperm inside the female
• Females store the sperm and may use it to fertilize many eggs
• Whale sharks give birth to live young – they are Ovoviviparous
Claspers
© MWSRP
© Scubasigns
2.5 REPRODUCTION & LIFECYCLE
• Pups are about 60cm long
when they are born
• Sexually mature at approx
9m or 30yrs
• Possibly live until 70 -100
years old
• Majority of whale sharks
encountered around the
world are juvenile males
© WWF Philippines
2.6 PREDATORS
• Do not have many natural enemies due to
their size
• Great white shark and killer whale
occasionally attack adult whale sharks
• Young sharks found in stomachs of smaller
sharks and swordfish
© Dennis Kaandorp