I noticed this video on YouTube among those featured on the main page, and it makes me wonder about otter behavior beyond the “Awww”s from the crowd;
In the wild, sea otters wrap themselves in kelp when they go to sleep so they don’t drift away. While there are predators within the kelp environment, the chances of getting hit by a great white shark are greater at the surface outside of the kelp forests. I can’t help but wonder if this “hand holding” behavior from the aquarium stems from the need to feel secure when asleep, a wild behavior that has been deferred to one that merely looks cute to the casual observer. Even if I’m wrong in the sense of the otters need to feel physically connected to something else, perhaps it reflects the need to feel (dare I say it) emotionally secure. For those who have read the book Born Free, you’ll recall Elsa was described as sucking Joy Adamsons thumb whenever she felt nervous. What reason the otters would have to feel nervous/insecure in the aquarium, I don’t know, but I can’t rule it out. If the otters are indeed a “couple,” other mammals have been known to have pair bonding behaviors, some primates sitting together with tails entwined during their courtship. Granted, the examples of Elsa and primates may not apply because behavior is not standard across the board for mammals, but I simply bring them up to convey the possibilities for why this behavior was exhibited. While I have no proof and I’m not an expert, I prefer the physical security hypothesis, but I could be entirely wrong.
Update: Upon some further research, there seems to be anecdotal evidence of otters sleeping together in groups called “rafts” and holding paws to stay together, a phenomenon also seen sometimes with youngsters and their mothers. Once again, whether this is for physical security, emotional security, or (likely) some combination thereof is not mentioned. In my opinion, it probably serves a dual purpose of making the otters feel physically secure and also assists with bonding of individuals in a group, so it seems to be advantageous from either viewpoint. Also, I owe a thank-you to WordPress for featuring this post as the “Blog of the Minute.”
In considering the question of how giraffes got so tall, it’s important to take into account the various aspects of their life history, birth being one of the high points. Here’s some video from the PBS documentary “Tall Blondes” (there’s a halfway decent companion book of the same name) featuring the birth of a baby giraffe;
There’s also video from the San Francisco Zoo showing a first-time mother giving birth, which is interesting in contrast with the “smooth” birth in the first video;
It’s somewhat interesting to consider that the giraffe has been adapted into a long-legged, long-necked form but there doesn’t seem to be any behavioral adaptation to reduce the fall of the offspring when its being born. While such births are often recorded for documentaries, I have to wonder what the mortality rate is for giraffe births, i.e. if any are done harm by the initial fall. How do such rates differ from the mortality rates of other African browsers like gerenuks? While we’re at it, what are the mortality rates among giraffes at different times of life, and what causes those deaths?
I also think that some relatively simple comparative anatomy might help answer some questions about form & function in giraffe evolution. Why not take measurements of upper leg (humerus/femur to radius & ulna/tibia & fibula) of various browsers in the same ecology as giraffes over their evolutionary history and determine what advantages the differing lengths might have as far as running/walking speed or efficiency. Giraffes certainly couldn’t have achieved their long necks without changes to their leg length as well, and the more we can understand and compare about each of the components the better we’ll be able to understand the evolution of the organism rather than just an aspect of an organism.
While I’m speculating, I also have been thinking about the sexual selection model of giraffe evolution that has been proposed and debated. Personally, I don’t find the male combat aspect of it particularly convincing, but this doesn’t mean sexual selection would not be valid; giraffes are derived from shorter-necked ancestors and so the “necking” behavior exhibited by extant males may have developed once a longer neck had been established. What if giraffe ancestor females preferred males with longer necks or if such males had a higher chance of intimidating other males (being a “winner”)? Then, a longer neck would be favored through sex and through an advantage of browsing a larger area, being doubly effective. It is important to note, however, that the necks could not extend on their own; legs and other systems would have develop along with the lengthening of the neck. The development of the giraffe’s specialized circulatory system (when it happened, precisely how it happened [were there relatively long-necked giraffes without it that didn't fare well?]) is also a big question, but if the mystery of the giraffe can be deciphered perhaps it will not only benefit us in the breadth of our knowledge, but also through using a more integrated approach to evolutionary study. Hopefully one day I’ll be able to study them in their own habitat (else what I do is primarily hypothesis without observation), and perhaps then I’ll be able to answer some of my own questions.
In quest to develop a somewhat intelligent post about giraffes and their evolution, I came across this video of a spotted hyena eating a giraffe from the inside out, literally lying down in the dead animals body cavity and having a grand old time (warning: it’s a bit messy)
While hyenas are often shown hunting in groups (or more often trying to steal lion kills in groups) many hunt on their own and are very effective solitary hunters. This is not to suggest that this hyena actually took down this giraffe, but it is important to note that hyenas do often hunt on their own. Why this one is alone with a giraffe carcass, without harassment from other hyenas, lions, or other scavengers however, I don’t know. Anyway, back to the carnage;
Dobson says that if you can’t proselytize about your faith all the time, you’re not a Christian, but according to this website, if you don’t speak in tongues you haven’t really got the holy spirit and aren’t a Christian either. I was tipped off to this nonsense by a commenter (who I’m assuming either made or agrees with the website), and it’s more of the “My religion is better than your religion” BS. According to the website, the Holy Spirit was recalled during the fraction of a second between 610/611 AD, and was not received by anyone again until the split second between 1900/1901 AD (1290 years of “the abomination desolation”). From what I’ve seen, especially in the documentary Jesus Camp, speaking in tongues is a big time requirement, many people often induced to the point of having seizures in order to be sure they have the holy spirit. Contrast this with a lady who came to Rutgers the other day proclaiming that if you weren’t Catholic, you’re going to hell, and I can only imagine what fate they believe a critic like me would receive.
What’s more disturbing is the main page’s proclamation that nuclear war is the sign of the End Times, which of course flows into the idea that if a nuclear holocaust can be brought forth sooner, God will come back sooner (the old “Well, it happened so God must have willed it to happen” defense). Just what we need; more people thinking God will reward them for annihilating everyone else.
This story is a bit old (this news article dates it at January 12, 2004) but it follows in the theme of Biblical idiocy that seems awfully prevalent today. I’ll let the video speak for itself;
While most people don’t actually want to end up in a lion enclosure, there are many zoos in which it’s excessively easy to get close to big carnivores. I wonder how often events like these occur (I’ll post about it should I find a disturbing trend of yahoos feeding themselves to lions).
With shows like BibleMan on the air, I’m glad I can’t afford television. The evangelical answer to the Power Rangers and other such shows, Bible Man is concerned that Billie is talking back to his mother and other equally heinous threats to the world. The quality isn’t the best, but the dialog in this scene is priceless;
The particular episode I caught on the Trinity network today (and tipped me off to the existence of BibleMan) featured a young boy who was getting into scuffles with other 12 year olds all the time. When confronted by the foam-rubber clad Christian, the child demanded to know why his parents were killed by a drunk driver if God really loves him. The response he got, after the stiff, hulking hero sat down on the bed, was the standard “I don’t know, but God has a plan for us” tripe. At that point I changed the channel; I couldn’t take it anymore.
There has been quite a lively discussion going on lately (see here, here, here, here, here, and here for some of the highlights) over science labs for undergraduates, and being that I’m an undergrad myself (and have 2-3 lab courses every semester) I thought I would weigh in on the subject.
First, I should be honest and say that I’m none too happy with my undergraduate education up to this date. There have been some high points and some low, but especially since I started reading more scientific books and papers on my own, I don’t feel like I’m getting much from any of my classes. It may sound arrogant, but half the time I feel I could teach some classes better than my professors (becoming that insufferable know-it-all everyone hates in the process), and at this point college has merely become the institutional meat-grinder that I have to go through if I want to get my degree and some amount of respect. Darwin had publish a massive work on barnacles that took 8 years, I have to spend 8 years avoiding the BS; means to an end as far as some amount of academic respect.
Before I go off on my rant, I have had some positive experiences with lab work. Although my actual paleontology lab involved little more than looking at fossils and taking notes, the class did take a trip to the Inversand marl pit in southern New Jersey, where I was able to collect some bone material (there’s too little to ascertain from what, but likely a marine reptile) including a crocodile scute and mosasaur vertebrae. Certainly, neither was a big scientific acheivement but I felt utterly exhilarated uncovering part of an animal that lived over 65 million years ago right around where I was standing (the area was about 100 feet underwater during the end-Cretaceous). Another such positive experience occurred last summer when I spent one week in Stokes State Forest and another in Barnegat Bay, learning techniques for birding, forestry, etc. While I have to say I wasn’t particularly excited about the forestry/botany aspects of the first week, it felt good to actually be outside practicing methods used to determine various aspects of ecology rather than sitting in lecture.
If I had any other good labs experiences, however, I have long since forgotten them. Most labs I have taken have been horribly constructed and leave the student with little new information, certainly not reinforcing the concepts learned in lecture. Indeed, for some classes “Lab” merely means “video time,” where ancient National Geographic programs are shown without further discussion or comment. Others, however, involve monitored viewing/experience with materials, such is my current biology 102 lab. Each lab starts off with a quiz and .ppt presentation, followed by viewing of ancient Turtox-brand slides and then a final wrap-up where each group is assigned a question. The past week has been an exception being that we’ve been dissecting a fetal pig, but it seems more about just being able to name the anatomy than understanding about how the systems work in the organism. Indeed, often it feels like the course is designed with future med-students in mind, important aspects of biology like behavior, evolution, and ecology getting little mention or being pushed to the end of the semester.
Part of the problem with biology courses, and labs specifically, is that lack of enthusiasm shown by instructors. What grad student really wants to get up early and set up 20 microscopes with slides and herd undergraduates for 3 hours? I have yet to be through the system myself, but from what I understand if you cannot pay for grad school on your own, you need to get a GA or TA-ship, meaning if you can’t get a grant and you can’t pay on your own, you have to be a TA. I don’t want to paint all TA’s with too wide a brush (maybe it’s just Rutgers) but most of the ones I have encountered aren’t particularly happy about their situation and do little to inspire undergrads. Indeed, there are professors as well that seem like they would much rather be doing their own research than teaching an introductory course, and this apathy (and even contempt) comes across quite clearly.
Like I said, I don’t want to say that all labs are worthless or that every college is like mine, but as far as my own experience, I feel that I’m merely paying for my degree in yearly installments. There’s little that I’ve learned through my classes that I actually remember, and whenever I’ve shown an interest in a particular field or a desire to get involved, I’ve been brushed aside or looked down upon. When I switched my major to ecology & evolution, my adviser told me she didn’t think I could do it, and I’ve magically been reassigned to someone else (although it’s probably for the better). I’m tired of sitting in cramped lecture halls and listening to dispassionate professors stumble through lessons, I actually want to LEARN something and become a professional, but it doesn’t seem like I can do so at college. While gaining a “well-rounded” education is important, I think things are made more difficult on students by having to balance biology, chemistry, physics, math, history, etc. all in the same semester through much of their undergraduate work; if the classes had a common theme, were integrated, or even fed into each other, I think the acquiring and retention of information would be much greater, but I know that I have chosen my classes poorly in the past and now am stuck playing “clean up” in order to get my degree in the next year.
Sometimes I wonder if I’ll ever make a good scientist at all, not for lack of interest or passion, but because I simply can’t stand the Ivory Tower of academia. I would absolutely love to go to Africa and study ecology and evolution there, but no one will take me seriously or even support me without having gone through the collegiate initiation process first, even though it has really done little to spur my intellectual development. There must be a better way.
We’ve known for some time that large species are being eliminated at a rate that could essentially wipe them out, and yet little has been done to mitigate this problem. After Jaws came out, sharks were primarily hunted as trophies or as symbols of manhood, but during the 1980’s commercial fishermen were told to turn to sharks as an alternative for other fish on the decline. This, of course, backfired and sharks continued to suffer, all the while the atrocious practice of finning (cutting a sharks fins off and dumping the rest of the body back into the ocean, often still alive) went on to supply traditional remedies/cuisine to Asia. According to this LiveScience article, we’ve now reached the point were large sharks are no longer effective as apex predators in some areas (primarily the East Coast of the US), and smaller sharks and rays are no longer kept in check. In addition to the sick and dying fish, sharks eat other sharks and rays regularly, and now that the large sharks are gone the smaller ones are not kept in check and decimating their food supply, which will in turn lead to a population crash when their food runs out and a large swath of major marine predators will be gone.
Part of the problem is that we can detect the effects of reduced shark populations, but we have no idea how many there really are. Sure, sharks get some protection and we know their numbers are declining, but management plans are exceedingly lacking in population studies. Beyond the difficulty of figuring out a marine organisms population size, there doesn’t seem to be that much interest in sharks. Last fall, I went to one of the “big wheels” of the marine science department telling him I wanted to get involved with shark ecology and population studies, to which he replied “What are you ever going to do studying sharks?” There seems to be a realitively small group of scientists who study sharks, but not nearly enough to gather the type of data needed to protect the many species that are now in trouble.
Yesterday I posted about a new paper in Nature which, through phylogenetic study, suggests that modern mammal lineages diversified earlier than once thought and the extinction of non-avian dinosaurs did not increase the lineages diversity. PZ, Larry Moran, and Mike Dunford have all covered this story as well, but there is one important facet of the study that I think is missing from many of the discussions about it popping up around the blogosphere. If the paper does accurately reflect what occurred to lineages that would lead to modern monotreme, marsupial, and placental mammal groups, this does not mean that there was no diversification of mammals after non-avian dinosaurs went extinct. Indeed, the paper itself states the following;
The supertree therefore contains no evidence that the diversification rate of the extant mammalian lineages increased soon after non-avian dinosaurs went extinct. Although there is strong palaeontological evidence that mammalian diversity, driven by a massively elevated rate of speciation, generally rose rapidly immediately after the K/T boundary, there is in fact no conflict between the palaeontological and neontological interpretations of the known facts. Most diversifications immediately after the K/T boundary were in groups such as multituberculates, plesiadapiforms and ‘archaic’ ungulates, as plots of the numbers of genera known in each sub-epoch indicate. These groups declined or went extinct early in the Cenozoic era and so are barely, if at all, represented in the phylogeny of living species. The continuing low rates of extant mammalian diversification through this period imply that the dearth of Palaeocene crown-group fossils is a real reflection of the low diversity of those clades. The low rates are also consistent with (but not direct evidence for) the hypothesis that extant lineages were inhibited in some manner by the diversity of the predominantly Palaeocene groups, and only started to diversify with the decline of the latter. However, like most other proposed competitive exclusion scenarios (for example, see refs 24, 25), this conjecture is based purely on the negative correlation of taxon diversities rather than direct evidence of exclusion.
While this may be a “minor” theme of the paper, I find this aspect of it particularly exciting. If the study is correct, then extant mammal lineages diversified once before the K/T extinction, but did not do so again until later when many of the other “archaic” mammal groups became extinct. Indeed, it almost seems like modern mammal groups could not catch a break, and if this holds up it would be extremely interesting to find out why now-extinct mammal groups were so successful while extant groups were not, and what caused such a reversal in fortune. Even forgetting about the K/T extinction for a moment, if mammals diversified long before the extinction, what led to this diversification? These are questions that certainly beg answers.
While the idea that extant mammals like opossums crawled out of the ash a little after the K/T extinction and led an unstoppable march of progress towards you and I is preposterous, I can’t see how the extinction of many groups of animals would not “set the stage” for further diversity and evolution. The process was likely more chaotic than previously thought, but it seems apparent that some (now extinct) mammal groups did diversify in the wake of the K/T extinction, although the reasons for this will require further investigation. I’m sure that there will be some debate over this paper for a long time to come, but hopefully paleontologists, paleoecologists, and those undertaking phylogenetic studies will be able to communicate each other to make sense of the fossil and genetic data. Either way, the extinction of the dinosaurs did mark a major landmark for mammals, and how all members of that group responded to the changes around them is something that will require much more study to ascertain.
Bininda-Emonds ORP, Cardillo M, Jones KE, MacPhee RDE, Beck RMD, Grenyer R, Price SA, Vos RA, Gittleman JL, Purvis A (2007) The delayed rise of present-day mammals. Nature 446:507-511.
This is the blog of Brian Switek, a (hopefully) soon-to-be-graduating student at Rutgers University studying ecology & evolution. Here you'll find ramblings and the occasional asinine assertion involving evolution, intelligent design/creationism, conservation, paleontology, and a myriad of other topics that occupy his mind on a daily basis. What, exactly, is Laelaps? Find out here. Other questions, problems, or trauma can be addressed to evogeek_at_gmail_dot_com.