Arxiu d'etiquetes: giant squid

The Loch Ness Monster and Yeti: Do they exist?

The Loch Ness Monster, Yeti, Chupacabras, Bigfoot, Kraken… we’ve all heard about them once and we even doubted their (in)existence. What is the truth about these creatures? Are they real? If not, what answers gives science to refute it? Find out in this article.

CRYPTOZOOLOGY

Cryptozoology is a pseudoscience, uses scientific terms but is based on beliefs rather than evidence and does not use the scientific method. It tries to find animals that have not been confirmed by science, called cryptids. Usually are beings appeared in myths and legends, but also extinct species that it ensures they have been seen at present, as the thylacine or dinosaurs (non-avian ones). You just have to do a search in internet to find fake photos that won’t mislead the most gullible person, but when the stories are installed in the collective memory, supporters of cryptozoology increase.

sirena, juan cabana, sirena real, mermaid, real
The siren of Maracaibo, an internet viral cryptid. Despite being a sculpture of Juan Cabana, some people still believe in these fake beings. Photo: unknown

Cryptozoology usually tries to add features of real animals to cryptids to make them more credible, and even appropriates of the species discovered by biology (zoology), like when they say the Kraken is actually a giant squid.

THE LOCH NESS MONSTER

Nessie it is the most famous cryptid, a gigantic aquatic animal which is supposed to live in Loch Ness in Inverness, Scotland. As with all cryptozoological beings, evidence of their existence are fuzzy pictures and testimonies of sightings. Surely you’ve ever seen the most famous photo of the Monster:

 nessi, 1934, photo of the surgeon, the loch Ness monster, loch ness, monster
The first photo of Nessie, shot in 1934, was considered (and is considered) an evidence of their existence. 60 years after, Chris Spurling confessed that it was a fraud. Photo: Marmaduke Wheterell

This one, like all photos of the monster, have been proved to have been farces and frauds. However, they continue to fuel the myth: the annual profit in this part of Scotland are of several million euros. It is  not surprising that many lakes around the world have their own monster like Nahuelito, Caddy, Champ, Manipogo, Ponik …

WHY THE LOCH NESS MONSTER CAN’T EXIST ?

  • Its age: the first reference of a being in this lake dates back to 565. So today it would be… 1451 years old, much more than the oldest known animal: Ming the clam (507 years old). Or even more, as some cryptozoologists argue that it could be a plesiosaur or a similar animal (extinct over 65 million years ago) about 20 meters long and 10-20 tons.

     Loch Ness, otter, elephant
    Or maybe it was just an otter… Photo: Jonathan Wills
  • Origins: if it was an animal from the Age of Dinosaurs, or their descendants, it is impossible to have always lived in the lake, which was frozen since the last Ice Age until about 12,000 years ago. There are no ways of connection within the lake and the sea, there are no sightings of the montser outside the lake, so ti could never go out to the sea to feed, for example.  Assuming also Nessie was an aquatic reptile, his preference would be subtropical waters, not the cold waters of Inverness (6 ° C on average).
  • Family of Nessies: the only possible explanation for the continued existence for thousands or millions of years, is that there are no one, but at least 100 individuals like Nessie to keep a viable population, according to population ecology. The minimum viable population is the smallest isolated population having 99% chance to stay alive for 1000 years (Shaffer, 1981). In addition, the Loch Ness is 56.4 km long and 226 m deep, there is an obvious lack of space for all of them (in addition to that sightings would constant).
  • Lack of corpses: in the case that there was a group of plesiosaurs, sooner or later their bodies should appear in the bank and no one single corpse has been found.

    Elephant swimming. In 1933, the year with more sighntinghs, a circus toured the area. Its elephant apparently bathed in the lake several times. Photo: Jeremy Tucker
  • Insufficient food: the lake is deep, long and narrow (32 km x 1.6 km). As the base of the food chain on Earth are plants, in aquatic areas are phytoplankton, algae and plants that can sustain herbivores and carnivores. Loch Ness has a little surface area exposed to the sun, so do not get enough sunlight to do a massive photosynthesis. In addition, the water is dark because has turf in suspension, preventing the existence of light from a few meters depth. It is so unproductive that it could not survive a predator of more than 300 kilos. Obviously, there are few animals that are totally insufficient  for feeding one or more animals of 20 tonnes.

    cadena trofica, red alimenticia, xarxa tròfica,
    Food chain of a freshwater environment. The arrows indicate the direction of energy from one link to another. Picture: unknown
  • Lack of evidence with the latest technologies: BBC has tracked the lake several times with sonar and satellite navigation technology with negative results. Neither mini-submarines or 24 hours webcams have found no sign of the monster.

    THE YETI, THE ABOMINABLE SNOWMAN

    The second most famous cryptid is a giant bipedal ape living in the Himalayas. Or in North America (Bigfoot), Canada (Sasquatch) Almasty (Russia), Hibagon (Japan), Yowy (Australia)… Like Nessie, Bigfoot moves millions of euros/dollars and each country has its own. Also is suggested that could be some kind of extinct hominid, a Neanderthal, a  Homo erectus or a Gigantopithecus .

    yeti, huella, footprint, petjada
    Photograph which revived the legend of the Yeti (1951). Photo: Eric Shipton

    As with all cryptids, evidences are based on eyewitness sightings, blurry photos or with doubtful origin. But in this case there are hair samples ensuring that belong to the Yeti. What science says ?

    DNA ANALYSIS

    The current understanding of genetics has allowed us to establish a more precise family relationships and identify living beings through analysis of DNA. So Bryan Sykes (Oxford University) led a study that analyzed more than 30 hair samples preserved in Buddhist temples, museums and private collections. Result: horsehair, bison, human, raccoon, cow, wolf, coyote… but none of the Yeti .

    The good news for zoology is that two hair samples match the DNA of a polar bear fossil, which could belong to a bear species unknown until now or a variety of polar bear of another color (golden-brown).

    PAtterson-gimlin film, bigfoot
    The most famous photo of Bigfoot is a snapshot of a video taken by Patterson-Gimlin

    THE CHUPACABRAS

    The Chupacabras (“goat-sucker”) is supposed to be a creature that kills and sucks the blood of farm animals without spilling a drop. Definitions are multifarious, bright red eyes, scales, bipedal, spikes on the back… also alleged dead Chupacabras are reported:

    mexico chupacabras
    The alleged chupacabras carcasses are usually canines with scabies who have lost hair, raccoons, or in this case a flying fox. Photo: unknown

    The Chupacabras has the distinction of operating in latin countries: Venezuela, Puerto Rico, Mexico, Argentina, Spain, Chile… The alleged habitat of chupacabras clashes with biogeography: a branch of science that studies the distribution of living beings on our planet .

    Knowing a basics of biological evolution and climate we can think like biogeographers: species are distributed according to their habitat and have adapted to the different areas and climates. No one would think of a frog living in the Sahara desert, for example. But Chupacabras seems to not care: inhabits a huge variety of landscapes between two continents and several islands, but of course, has a predilection for Spanish-speaking places. Nothing to do with biology: it is the product of a legend of oral tradition.

    ZOOLOGY VS CRYPTOZOOLOGY

    In conclusion, zoology is the branch of biology that to certify that it has discovered a new species must:

Voyage to the bottom of the deep sea (II): Biodiversity in the deep sea

This week we are continuing our voyage to the bottom of the deep sea. While last week we focused on the adaptations that fishes have suffered, this week we are focussing on the biodiversity. In concrete, we are explaining crustaceans, squids, cnidarians (corals, jellyfishes and anemones), fishes and worms. 

INTRODUCTION

In 1840, the scientist Edward Forbes concluded that there wasn’t life under 550 meters depth. Nowadays, it is known that this is not true because recently it has been found a fish at 8,100 meters. It has been determined that the relative abundance of animals depends on depth. In fact, in general terms, the abundance decreases with depth, but this don’t exclude that there are a lot of species.

 

BIODIVERSITY

CRUSTACEANS

Amphipods are by far the most abundant crustaceans in the deep sea. They are small animals with the body compressed laterally and without a carapace, which feeds on carrion and live inside cavities made by themselves in the sea floor. These small animals are transparent, except for them eyes, which are red due to a pigment in the retina.

amphipode-abysseDeep sea amphipod. They are characterized by the presence of a transparent body with red eyes. (Picture from http://www.astronoo.com/es/articulos/bioluminiscencia.html)

Other deep sea crustaceans are stone crabs, with a carapace of 7.5 cm length and legs of about 15 cm; the armoured shrimp, one of the species that lives at 6,000 meters and has a length of 7 to 10 cm; and more.

DEEP SQUIDS

In spite of the general thinking that deep sea squids are all large, like the giant squid, which can achieve a length of 18 meters; the truth is that this is an exemption because there are some spices of just 4 cm. They hunt with the suckers in the tentacles and driving the prey to the mouth. Most of these squids are bioluminescent and can regulate the colour, the intensity and the angular distribution of the light.

The Humboldt or jumbo squid (Dosidicus gigas) lives in the western coasts of Central and South Amercia and can achieve a length of 4 meters, which feeds on fishes and practise cannibalism.

Dosidicus_gigasHumboldt or jumbo squid (Dosidicus gigas). They have bad reputation because they attack divers.

CNIDARIANS: CORALS, JELLYFISHES AND SEA ANEMONES

Differences between shallower cnidarians and deep ones are due to differences in the food distribution. In the deep sea, anemones and corals don’t have directly phytoplankton and zooplankton, and they depend on the nutrient rain from the shallower waters of the ocean. On the other hand, jellyfishes have a slow metabolism to survive in hard conditions. It supposes slower growth, but a longer life.

To give an example, this crown jellyfish inhabits between 200 and 2000 meters depth and can measure until 15 cm. It feeds on small crustaceans and organic matter. Its red colour let them be camouflaged in the environment. In addition, they are bioluminescent animals.

Atolla wyvillei[3]Crown jellyfish. Its red colour let them be camouflaged in the environment.

Deep-sea jellyfishes are voracious predators, but also can be a prey for some fishes. They produce light discharges to attract small animals. To dissuade predators, they expel a brilliant particles stream.

An habitual feature of deep-sea jellyfishes, but also present in other groups, is gigantism. It means they are bigger than their equivalents in the shallow ocean. The possible explanation to this could be that bigger animals are more efficient than smaller to get food when the environmental conditions are almost constant during long periods of time.

FISHES

Gonostomatidae fishes are the most abundant vertebrates in the Earth and live in the mesopelagic zone. Together with the lantern fishes, they represent a 90% of the captures in the pelagic trawling fishery. Deep-sea fishes usually have a length between 2,5 – 10 cm and a thin and soft body, but there are exceptions.

There are some examples here:

  • Anglerfish: These fishes inhabit in the deepest parts of the oceans and present the optimal colouration to absorb the few light that arrive and, in this way, to be camouflaged. They present a light in the end of the antenna, which let them to capture preys.

Anglerfish
Anglerfish

  • Spiny lantern fish: Because of its silvery body, this fish is not much vulnerable since its contour can’t be seen clearly. In addition, spiny lantern fish presents a bag in the eye with bioluminescent bacteria.

Pez linterna espinoso
Spiny lantern fish

  • Pelican eel: This animal can measure 2 meters long. Its enormous mouth are connected directly to the stomach.

Pelican eel
Pelican eel

  • Tripodfish: Tripodfish has long prolongations in its pelvic and caudal fins, which let them put on the sea floor, while it is waiting for its prey.

Tripodfish
Tripodfish

  • Black swallower: This small fish has the ability to dilate a lot its stomach and, in this way, it can swallow preys bigger than itself.

Black swallower
Black swallower

 

MARINE WORMS

Deep-sea worms can be from microscopic to measure 2 meters long and are one of the most abundant and different invertebrates. They can be of different groups: polychaetes, tubular worms, sipunculids and equiurids. They live partly or totally buried in the sediments.

Tubular worms usually live in big groups near to thermal springs and present red bright gills as a consequence of a high level in hemoglobin to absorb oxygen. In addition, they can retain sulfurs, which will be used for symbiotic bacteria.

Riftia_fish_EPR_Kristof_Lutz-pTubular worms. They use the sulphur produce in the thermal springs thanks to symbiotic bacteria.

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