How big can whale shark open it's mouth?

Answer 1

I have seen this erroneously answered at a few inches which is false. The whale shark has the ability is constrict the esophagus to keep water out and hold food in the stomach. Water is pushed into the huge mouth at great force and then forced through tubes out of the gill flaps allowing the massive amounts of food to be swallowed. Depending on the size and age of the fish it can vary. The notion that the esophagus is to small to swallow large amounts is false. This article shows that huge volumes of food are swallowed with each mouth full. http://www.washingtonpost.com/wp-srv/nation/pdfs/Sharkfeedingpaper.pdf this site tells you all you need to know about the whale shark esophagus, mouth size, and how much it can swallow.

Anatomical measurements indicated maximum internal mouth

width was 12.0% (N = 8), and mouth height 6.3% (N = 10) of TL, and

the open mouth width to height ratio was 1.9 (N = 10). Internasal

width was 10.0% of TL (N = 11), and vertical mouth height/internasal

width was 0.61 (N = 11). Based on open mouth internal heights, the

estimated total open mouth area was 2035 cm2

for shark A (622 cm

TL), 1841 cm2

for shark B (593 cm TL), and 1079 cm2

for shark C (443 cm TL) (N = 4 frontal pictures of feeding sharks).whale shark swimming at 1.1 m/s.

The biomass ingested was estimated by calculating the volume

of water passing through the partially submerged mouth per unit time multiplied by the mean biomass of plankton per unit volume. With an average of 84.7% of the open mouth underwater during

surface ram filter feeding, a 443 cm TL shark would present an open

mouth area of ∼914 cm2

(84.7% of 1079) and a 622 cm TL shark

an open mouth area of ∼1724 cm2

(84.7% of 2035) to the water.

With a flow velocity at the mouth of 0.99 m/s (90.4% of 1.1 m/s) the

smaller shark would filter 0.0914 m2

× 0.99 m/s or 0.0905 m3

/s of

water = 326 m3

/h, and the larger shark would filter 614 m3

/h. With

an average plankton biomass of 4.5 g/m3

at the feeding sites, the

sharks would, on average, ingest 1467 and 2763 g of plankton per

hour, respectively, and for an average feeding time of 7.5 h per day,

a total of 11,003 and 20,723 g of plankton/day, which at 1.357 kJ/g equates to 14,931 and 28,121 kJ per day, respectively.....

Answer 2

4.9 feet.