Thinking Citizen Blog — Wildlife (IV) Cetaceans (Whales, Dolphins, Porpoises)
Thinking Citizen Blog — Wednesday is Climate Change, the Environment, and Sustainability Day
Today’s Topic: Wildlife (IV) Cetaceans (whales, dolphins, porpoises)
Cetaceans are all carnivores. Even the very sweet, and kind-looking dolphin, “Flipper.” Don’t tell the kids. This week I came up with a few more surprises as I did a little research on these amazing aquatic beasts. Experts — please chime in. Correct, elaborate, elucidate.
THE TERMS “WHALE” AND “DOLPHIN” ARE INFORMAL NOT SCIENTIFIC TERMS
1. Technically, the “infraorder” of “cetaceans” consist of two “parvorders”: balleen whales (mysticeti) which use keratin-based bristles to filter food (you could call them tooth-less whales) and toothed whales (odontoceti).
2. There are four families of toothless whales: right and bowhead whales, pygmy right whales, rorquals, and grey whales. I have skipped the scientific terms for these. Too much is too much.
3. There are ten families of toothed whales: including four commonly called “whales” (belugas and narwhals, sperm whales, dwarf and pygmy sperm whales, and grey whales). Porpoises have only one family. And dolphins have five.
NB: The five dolphin families are: oceanic, South Asian river, old world river, new world river, and La Plata. Whew! How much of this can I possibly remember? Someone should come up with a Cetacean song! Maybe someone already has…
WHAT A FLUKE! WHAT THE FLUKE! FISH DON’T HAVE THEM!
1. I love learning new words. Today I learned that cetaceans don’t just have fins — they have flukes!
2. That would be the horizontal part of their tails!
3. Fish don’t have them, but mermaids do!
NB: Flukes “increase the propulsion area driven by the back muscles.” A blue whale’s fluke can be 25 feet wide! Yikes! “The portion of the whale’s body that tapers to the flukes is called the caudal peduncle.”
WHAT IS A “WHALE FALL”? Deep water ecosystems all their own.
1.”Upon death, whale carcasses fall to the deep ocean and provide a substantial habitat for marine life. Evidence of whale falls in present-day and fossil records shows that deep-sea whale falls support a rich assemblage of creatures, with a global diversity of 407 species, comparable to other neritic biodiversity hotspots, such as cold seeps and hydrothermal vents.”
2. “Deterioration of whale carcasses happens through three stages. Initially, organisms such as sharks and hagfish scavenge the soft tissues at a rapid rate over a period of months and as long as two years. This is followed by the colonization of bones and surrounding sediments (which contain organic matter) by enrichment opportunists, such as crustaceans and polychaetes throughout a period of years. Finally, sulfophilic bacteria reduce the bones releasing hydrogen sulfide enabling the growth of chemoautotrophic organisms, which in turn, support organisms such as mussels, clams, limpets and sea snails. This stage may last for decades and supports a rich assemblage of species, averaging 185 per site.”
3. “Whale falls are able to occur in the deep open ocean due to cold termperatures and high hydrostatic pressures. In the coastal ocean, a higher incidence of predators as well as warmer waters hasten the decomposition of whale carcasses.”
NB: “Carcasses may also float due to decompositional gases, keeping the carcass on the surface. The bodies of most great whales are slightly denser than the surrounding water only become buoyant when the lungs are filled with air. When the lungs deflate, the whale carcasses can reach the seafloor quickly and relatively intact due to a lack of significant whale fall scavengers in the water column. Once in the deep-sea, cold temperatures slow decomposition rates, and high hydrostatic pressures increase gas solubility, allowing whale falls to remain intact and sink to even greater depths.”
Click here for the last three years of posts arranged by theme:
PDF with headlines — Google Drive
Please share the coolest thing you learned in the last week related to climate change or the environment. Or the coolest, most important thing you learned in your life related to climate change that the rest of us may have missed. Your favorite chart or table perhaps…
This is your chance to make some one’s day. Or to cement in your own mind something that you might otherwise forget. Or to think more deeply than otherwise about something dear to your heart.