part 2: biology & ecology © scubasigns. part 2: biology & ecology outline 1. taxonomy and...

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 cycle How do they reproduce?

6. Predators Which animals prey on whale sharks?

• 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 hydro- dynamic

• It has several rows of replaceable teeth

Teeth always sharp

The whale shark is a true shark:

2.1 TAXONOMY & CLASSIFICATIONTrue Sharks

•These features have made sharks successful animals

•Appeared 220 million years before the dinosaurs

• 440 different species of shark

• Can exist in many different habitats- even fresh water!

2.1 TAXONOMY & CLASSIFICATIONShark Success

Bull sharks and river sharks happy in fresh water rivers

Smallest is lantern shark just 17 cm long

A primitive six-gilled frilled shark

2.1 TAXONOMY & CLASSIFICATION: Shark Orders

2.1 TAXONOMY & CLASSIFICATIONcarpet shark features

Nostril barbells

Prominent ridges

2 dorsal fins

Mouth at the front of the head

2.2. DISTRIBUTION & HABITAT

• 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

© Morgan Riley

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

•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’

2.3. ANATOMY & PHISIOLOGY:Mouth

© Scubasigns

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

• 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.

2.3. ANATOMY & PHISIOLOGY:Nostrils

© 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 & FEEDINGPrey

• Whale sharks feed on tiny prey (>0.5mm) including plankton, eggs and small shoaling baitfish

2.4 DIET & FEEDINGRam Filter Feeding

Whale sharks are constantly diving and ascending - possibly in search of food

They utilise ‘ram filter feeding’…

© Scubasigns

2.4 DIET & FEEDINGSuction Filter Feeding

……or ‘Suction’ filter feedingor ‘Suction’ filter feeding

•Suction filter feeding enables WS to feed on Suction filter feeding enables WS to feed on more mobile preymore mobile prey

• Because WS seek high densities of prey they Because WS seek high densities of prey they are often seasonal visitors to specific locationsare often seasonal visitors to specific locations

© Scubasigns

2.4 DIET & FEEDINGOther filter feeders• There are two other filter feeding sharks:

The Basking shark…

2.4 DIET & FEEDINGOther 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 OvoviviparousClaspers

© Scubasigns

© MWSRP

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