protecting teeth against environmental insults and responding to age-related and pathological conditions

other mammalian teeth are known to be capable of sensing external stimuli

tooth precursors as sensory organs

Changes to the interstitial fluid flow within dentinal tubules changes the conformation of odontoblastic cells connected to a pulpal nerve plexus which sends signals of sensory perception to the brain

acoustic probe (Best, 1981; Reeves and Mitchell, 1981), possibly associated with sound transmission

suggesting an environmental driver, possibly linked to an increase in Arctic sea ice.

We find relatively less variability in the distribution of heterozygosity across the narwhal genome (Table S4). This pattern is unique to the narwhal, as the other species have more similar variations in heterozygosity across their genomes.

We find that the low diversity did not arise by recent inbreeding, but rather has been stable over an extended evolutionary timescale. Our analyses show that the current large global abundance most likely arose due to a recent rapid population expansion around the onset of the Last Glacial Maximum and that genetic diversity may not have had time to increase accordingly.

high levels of inbreeding; or (3) a recent population expansion from a small founding population.

vulnerable Arctic marine mammals to ongoing rapid climate changes, especially due to its high specialization and restricted Arctic-Atlantic distribution

Low levels of genetic diversity have been observed across several narwhal populations using mitochondrial DNA (mtDNA)

make annual migrations between coastal summering grounds and offshore ice-covered wintering grounds

have shown that sperm whales are active predators that at times accelerate to speeds of more than 3 m/s during rapid changes in body orientation and sharp turns at depth

in general no tooth marks on ingested prey items

in old males, may constitute up to 1/3 of the body length

Occasionally, much larger squid such as jumbo, giant and colossal squid

Sperm whales are mainly teuthophagous predators that spend more than half of their life below 500 meters

Sub-Antarctic Front and Antarctic continent

It attains dorsal mantle lengths of ∼250 cm, and a maximum recorded total weight of 495 kg

Consequently, the assertions of Schmitz et al. [1] are insupportable and our suggestion that the huge eyes of giant squid are uniquely suited for detecting sperm whales remains intact.

the only large visible objects would be other animals triggering planktonic bioluminescence as they move through the water.

The eyes of giant and colossal squid grow to almost 3 times this diameter, even though this provides a relatively small improvement in visual range.

Schmitz et al. [1] explicitly assume that eyes are “expected” to scale allometrically with body size.

eyes of giant and colossal squid can grow to three times the diameter of the eyes of any other animal

22.7% of the 204 people billed as an expert, scientist, or researcher by Shark Week have no peer-reviewed publications

Violent programming is a market differentiator known to attract advertiser-desired demographics, particularly 18-34-year-old males

The number of programs began to increase dramatically after 2010, with the greatest number of unique programs (24) produced in 2018 and 2020

According to a post-show social media poll following “Megalodon: The Monster Shark Lives”, 79% of respondents reported believing that O. megalodon was still alive [36],

he movie Jaws (1975) marked a shift towards modern presentations of sharks with visceral visual immediacy.

At least 32% of all chondrichthyan species (sharks, rays, skates, and chimeras) are assessed as or estimated to be Threatened with extinction

– Jaws which depicted brutal shark attacks to cinema goers in 1975

Misperception fuels fear.

shark diving contributed US$ 42.2 million to the economy of Fiji

he fins are sawn off usually while the shark is alive, and the rest of its body tossed overboard into the water

Shark liver oil is extracted and sold for its ‘health benefits’, its jaws and teeth have been used to create souvenirs, and its skin is used to make ‘shark leather’ products.

25% of shark and ray species are threatened with extinction

Given the typically longer gestation periods (breeding patterns being in every second or third year), and the long time to reach sexual maturity, the ability for sharks to naturally recover their dwindling numbers is well-nigh impossible.

They also remove sick, diseased and injured animals in the waters.

A numerical estimate by the Marine Policy scientific journal estimates that 100 million sharks are killed by humans every year.