Ravenous, famished, starving. We all have hungry days, but are you ever 4 tonnes of seafood hungry?

Let's be honest, the blue whale, giant of the seas and the largest living animal on Earth, beats everything when it comes to a big appetite. On a daily basis, this leviathan gulps down 40 million tiny crustaceans known as krill to maintain its bulk.

But there are other animals with a reputation for supersizing their meals, and some of them might surprise you.

Like the blue whale, giant land animals have appetites to match their impressive stature. According to African elephant expert Norman Owen-Smith of the University of the Witwatersrand, Johannesburg in South Africa, adult males eat around 1% of their bodyweight in dry mass every day, while lactating females eat up to 1.5% to keep themselves going.

Pandas eat as much as 12.5kg of bamboo a day

Males can weigh as much as 6 tonnes, so that is up to 60kg (132 lb) of dry food – without factoring in the water content, which can make it four times heavier.

These mega-mammals are herbivores so they spend most of their day foraging for enough green matter to power themselves. They can feed for as long as 18 hours a day, depending on what is available.

Similarly, the giant panda spends 14 hours a day munching on bamboo. Researchers have suggested that this diet is not optimal for the animals, which actually have an omnivorous digestive system that is not best suited to breaking down lots of plant fibre. This could explain why pandas eat as much as 12.5kg of bamboo a day to get the nutrition they need – and why they produce such a lot of poo.

Generally, vegetarians must spend a lot of time at nature's buffet table to consume enough calories, while carnivores can focus on fast food.

Little brown bats are said to be able to devour 1,000 mosquitoes in an hour. But scientists view this figure with suspicion.

Brock Fenton of Western University, Canada, says the claim is "preposterous", the result of confusion between two studies of two different species of bat in the 1950s.

Japanese house bats plan their next meal before they have even eaten the current one

Fenton says that one study examined the stomach contents of a tricoloured bat after a period of feeding, while the other recorded little brown bats in a laboratory catching mosquitoes and fruit flies. Neither give an accurate picture of how many insects little brown bats eat in the wild.

Furthermore, little brown bats eat more than just mosquitoes: they prefer larger prey items, such as moths, when they can catch them. A study of the bats in Canada revealed that mosquitoes only made up a small proportion of their diet.

So, it is probably a bit of a stretch to say they can eat a mosquito every 3.6 seconds.

However, there is evidence to suggest bats really optimise their hunting strategies to make the most of the available prey. A 2016 study revealed that Japanese house bats plan their next meal before they have even eaten the current one. Far from winging it, the bats plan their flight routes according to what snacks they can pick up along the way.

There are other small brown mammals with an unshakeable reputation as voracious predators: the shrews.

The average hummingbird eats half its bodyweight in sugar every day

The common shrew must eat every 2-3 hours and consume 80 to 90% of its bodyweight in food each day to sustain itself. At half the size of its common cousin, the pygmy shrew eats 125% of its bodyweight every day.

These mammals have extremely fast metabolic rates, meaning they break down and use energy rapidly. So, they must feed regularly on high-protein invertebrate meals or face starvation.

Any discussion of metabolism will also feature hummingbirds.

These flying marvels favour a sugar fix to power their energy-intensive hovering flight. Beating their wings as many as 50 times per second, the birds have some of the highest metabolic rates among vertebrates.

You may have heard that the average hummingbird eats half its bodyweight in sugar every day, feeding every 15 minutes on floral nectar. But there are over 300 species of hummingbird.

It takes immense energy reserves to transform from a tiny larva to a silk moth

"The amount of nectar consumed can vary quite a bit by hummingbird species," says Adam Hadley, a leader in the hummingbird research team at Oregon State University. "Particularly since they have a very large range in body size, from the 2.5g bee hummingbird to the 24g giant hummingbird."

While the larger species consume more nectar overall, they burn their energy more slowly than smaller birds. This means that, proportionally, the smaller species are hungrier.

Hadley says the birds also store energy for when they need it. "Interestingly they can often be storing up as much as 17% of their body weight each day in fat reserves, so that would be like the average North American putting on 30lbs in a single day."

Other species only display a prodigious appetite at certain points in their lives. For example, it takes immense energy reserves to transform from a tiny larva to a silk moth.

The Polyphemus moth is named after Homer's mythical cyclops, because it has a single eyespot on each wing. But the man-eating monster and crop-devouring caterpillar are perhaps more similar in their gigantic appetites.

To match a caterpillar, we would have to eat 50-200lb of lettuce each day

According to the Guinness Book of World Records, this caterpillar can eat 86,000 times its bodyweight in 56 days. But Andrei Sourakov, collections co-ordinator at the Florida Museum of Natural History, says this is a dubious figure. It is a bit like measuring how much a person eats through their entire childhood, then comparing it to their weight as a newborn baby.

Sourakov says that a recent project at the University of Florida found that luna moths, a similarly sized species, typically ate between half and two-thirds of their body weight each day.

"Still, I think it is impressive," says Sourakov. "To match a caterpillar, we would have to eat 50-200lb of lettuce each day." Clearly, Eric Carle's famously very hungry caterpillar was not far off the mark.

Our final candidates for the hungriest animal on Earth are not likely to be the stars of a popular children's book. Even though their peculiar eating habits have been harnessed to save human lives, they have a reputation as vampires.

Medicinal leeches are famous for drinking blood, and have been used to heal wounds and thin the blood for centuries. However, most of the world's 700 species of leech are actually predators of invertebrates, like the worm-hunting monsters of Borneo.

Leech champion Mark E. Siddall at the American Museum of Natural History has seen "unnaturally huge" leeches in captivity, where they have easy access to food and no predators.

"The largest leeches I have ever seen are specimens of the giant Amazonian leech Haementeria ghilianii and of the Asian buffalo leech Hirudinaria manillensis," says Siddall. "These individual leeches no doubt consume the most blood."

But in the wild, opportunity dictates appetite. Jungle leeches that are too small to hunt must wait for their hosts to come along. Since the wait can be a long one, it is not surprising that they gorge themselves given the chance, swelling up to seven times their bodyweight with one bloody meal. That is a lot for anyone to swallow.

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