Talk:Cetacea

From Wikipedia, the free encyclopedia

	This article is part of WikiProject Cetaceans, an attempt at creating a standardized, informative, comprehensive and easy-to-use cetaceans resource. If you would like to participate, you can choose to edit this article, or visit the project page for more information.
B	This article has been rated as B-Class on the assessment scale.
Top	This article has been rated as top-importance within WikiProject Cetaceans.
	This article has been selected as the current Cetaceans Collaboration of the Month.
Cetaceans To do: Here are some tasks you can do, as organized by the Cetaceans WikiProject. If you are interested sign up on the project page: Copyedit/Formatting: Beaked whale Expand: Hector's Beaked Whale, Hector's Beaked Whale, Ginkgo-toothed Beaked Whale, Shepherd's Beaked Whale, Archaeoceti, Cumberland Sound Beluga, Blubber, Chinese River Dolphin, Humpback dolphin Requests: List of extinct cetaceans Stubs: Callosity, Cephalorhynchus Images: Images of porpoises are wanted. Featured/Good article candidates: Sei Whale Patrol: Look through the Category:Cetaceans for recent changes Collaboration of the Month: Cetacea Other: See the project page.

Contents 1 What does "fish" mean? 2 Cetacea or Cetacean? 3 Arteries/babies 4 Breathing in Marine Mammals 5 Blubber vs. Hair 6 Hearing 7 Taxonomy 8 H-lello Gentlemens 9 Broad Speculation

[edit] What does "fish" mean?

Since I was a young child, teachers have always asserted that "contrary to common thought, whales are not fish." I'm pretty sure that nowadays most everybody who knows what a "mammal" is understands that whales are mammals. But is it true that whales are not fish?

The word, "fish" was never intended as a phyologenic term. For centuries, it was understood to mean any sea-dwelling animal. Even crabs, mollusks, and the like are referred to as "shellfish." Historical literaty sources which refer to whales as "fish," (such as "Moby Dick," and, as many suppose, the Book of Jonah) are not wrong; they simply use a traditional definition of fish, rather than referring to the phylogenic classification of "pisces" and related classes. Actually, today, most biologists have moved many other "fish," such as sharks, lobe-finned fishes and hagfishes, into other classes; the phylogenic equation of "'fish' equals 'Class Pisces'" has totally broken down.

I agree about phylogeny, but when people speak of fish they are always mean something that has gills/"breathes underwater". Whales don't, so they're not fish.

[edit] Cetacea or Cetacean?

I prefer the English name Cetaceans to the scientific Cetacea. Just like the project name. Any agreement or disagreement? Nurg 11:13, 27 Nov 2004 (UTC)

I think the general policy of "no plural titles" has caused it be the way it is more than anything else. If we had it at Cetaceans, someone would move to cetacean, which to my mind sounds more awkward than both Cetacea and cetaceans. I guess being at the order taxon is a bit of a border between latin (for those taxa further up the tree) and English (for many of those further down). Pcb21| Pete 16:34, 27 Nov 2004 (UTC)

Oops, my slip with the plural. I meant to say I prefer the English name Cetacean to Cetacea. Like the project name but singular. I agree that Cetacean sounds a little more awkward than Cetaceans (which is why I made the slip) but so does every singular for a group of animals and I think we have to live with the singular vs plural decision. I don't think the taxo level comes into it - I prefer the English at every level, provided there is a suitable English term, which there isn't for some groups. Nurg 06:35, 28 Nov 2004 (UTC)

Cetacea is plural. Cetacean is singular. If the rule is "no plural titles," then Cetacea would violate that rule. The solution would be to use "Cetacean" or "Order Cetacea." But I would personally have no problem bending the "no plural" word for terms from foreign (including "dead") languages.

[edit] Arteries/babies

"A baby can crawl through the arteries of a blue whale!" (Discovery 2005).

Thanks. Actually we already note that oft-quoted fact at Blue Whale#Size. Shame that we don't have a source for big the artery actually is - some babies are pretty small. Pcb21| Pete 17:30, 2 November 2005 (UTC)

[edit] Breathing in Marine Mammals

That may sound like a stupid question, but I wonder how long marine mammals can stay underwater without breathing air into their lungs. I heard once it can be as long as 50 minutes in the case of certain species of seals and whales. Did their lungs evolve in some specific way to allow them to hold their breath for such extended periods of time ? Thanks for the information.

Yes marine mammals have spent millions of years adapting to being in water! According to the Encyclopedia of Marine Mammals, the Sperm Whale routinely holds its breath for 40 minutes and can do it for 75 minutes. The Elephant Seal usually dives for 25 minutes but can do so for 2 hours. Pcb21 Pete 09:54, 28 April 2006 (UTC)

[edit] Blubber vs. Hair

"After the cetacean's hair disappeared, it needed some way of preserving body heat. This came in the form of blubber, a thick layer of fat between the skin and the flesh that also acts as an emergency source of energy. In some cetaceans the layer of blubber can be more than a foot thick."

This can not have hapend, if indeed the hair disappeared it could not habe preserved body heat so it would die. It must have hapend around the same time (hairs getting tinner while blubber layer growing) or the other way around (blubber growing and then hair disappearing)

[edit] Hearing

"The ear bone called the hammer (malleus) is fused to the walls of the bone cavity where the ear bones are, making hearing in air as good as impossible. Instead sound are transmitted through their jaws and skull bones." contradicts "The inner ear, however, has become so well developed that the cetacean can not only hear sounds tens of miles away, but it can also discern from which direction the sound comes"

It is unclear, but is it a contradiction? Whales cannot hear (much) in air, but can in water. Pcb21 Pete 09:48, 28 April 2006 (UTC)

I found it clear, but will take a look at making it so to others. I've encountered information, long ago, about their increadible hearing abilities: vast range of frequencies, rate of processing (perhaps somewhat similar to thinking of sample rate in computer audio), ability to communicate over huge distances - hundreds or thousands of miles (sounds impossible, but I think that was said, and water + low freq would be much much more efficient than air, like elephants using low frequency sounds to communicate over distance - you hear the bass of the jerk with the loud car outside, not the treble, after all). Anyone have more information? This section could use some expanding or separate article. Thanks 146.74.231.113 19:14, 12 December 2006 (UTC)

[edit] Taxonomy

A recent anonymous editor substantially revised the taxonomic listing - essentially promoting several new species. I realise that the jury is still out on some genera where you made changes but in others the type has been widely recognised as a subspecies or synonym. I think the best we can do is to stick with the classification from the two major authorities (and note the differences between them). All further discussion is in, or will be added to (now that I have MSW3!) the relevant sub-articles. Thanks! Pcb21 Pete 09:48, 28 April 2006 (UTC)

[edit] H-lello Gentlemens

We are going to play a game. Somewhere in this article is a missing period.
If you cannot find that missing period in under twenty-four hours.. this bomb strapped to my chest will DETONATE! HAHAHHAHAHAH! Have fun! --Isequals 08:43, 20 June 2006 (UTC)

Though that was like six months ago, I took out a few random ones just to make sure he did it. :) 146.74.231.113 19:14, 12 December 2006 (UTC)

[edit] Broad Speculation

There seems to be some broad speculation in this article as to the origin of Cetacea. Yes, some hypothesize that Cetacea migrated from land. However, not nearly enough is known to establish that relationship. They may have started in the oceans, and evolved there from start to present. I would like to see this presented in a more unbiased fashion, and am adding a POV-check to the article to attempt to encourage this. Simply adding that "one possibility is that" may be enough.--216.227.83.45 20:58, 24 October 2006 (UTC)

There may be some debate as to whether they evolved from mesonychids, anthracotheres, or artiodactyls, but there is zero debate as to whether or not cetaceans evolved from land mammals. These aren't fish. Since this appears to be your POV issue, I'm removing the tag. --Aranae 01:15, 25 October 2006 (UTC)

Hmmm... I don't remember saying that they were fish. That doesn't mean that they started on land and moved into the ocean. Are lobsters fish? How about plankton? What did they look like before they "entered the water"? I put the POV tag there because the statement that they started on land is not scientifically valid, as there is no scientific data listed here to support the assertion. They may have started on land, and that may be one possibility. I'm fine with it being listed as a possibility, or conjecture. And I don't know what you are referencing when you say there is zero debate. I am leaving the tag off for now, and look forward to your reply.--205.231.145.172 01:50, 30 October 2006 (UTC)

Since there has been no reply, I am re-adding the POV check. There is no explanation as to the evidence that this order has absolutely evolved from land mammals, as opposed to always dwelling in the sea. Dogs (especially my retriever) love to swim in the water. They can also eat fish. Yet they have not lost hair, gained blubber, and taken to the sea.--216.227.56.70 15:24, 9 December 2006 (UTC)

The statement that they started on land is scientifically valid - i don't know where you are getting this information from. The article says ' cetaceans most likely evolved from land animals', so it does not say that for absolute certain they evolved from them. They are mammals, and they evolved from land mammals, which land mammals are not known for certain. The ability for a mammal to go in the sea does not mean that they will evolve into animals that will live in the sea for good. Where are you thinking they evolved from? Chris_huh^talk 16:23, 9 December 2006 (UTC)