Posts Tagged ‘cervidae’

Reindeer and Other Herbivors Determine the Tree Line – Not Warmth

December 3, 2010
Monday, 29 November 2010 11:17 Written by Gustaf Klarin, SR Vetenskapsradion
Original article here
It is not principally a warmer climate that is making the tree line creep upwards in many directions in the Swedish mountains. This is shown in a new study from the Torneträsk region in northern Sweden. There are several other factors that affect the spread of trees more than higher temperatures.

It is mainly grazing reindeer, insect attacks, and several other factors that affect the spread of the mountainous forest, more than the changed temperature situation.

“Tree line can go up, down or stay in the same position even during the same climatic period. That has not being showed before,” says Terry Callaghan, director of the Abisko Scientific Research Station.

Researchers were able to see that precisely reindeer grazing affects more than the temperature, since the tree line advanced furthest upward during the cold period that started in the late 1960s and continued through the 1970s, it was a time of fewer reindeer.

A warmer climate has more of an indirect effect through, for example, there being more insects that can damage trees.

Many climate models expect the forest in the tundra and the upper Arctic will expand heavily northward in the next hundred years because of higher temperatures. But the new research indicates that the assumptions may be grossly inaccurate. The effect of grazing reindeer and moose must be reckoned with.

“We can not just expect the tree line to move northwards, we have to look in more detail,” Terry Callaghan says.

Heavy Metals May Influence Moose Health

November 13, 2010

Bull moose. Moose in southern Norway are in significantly worse health than those further north and in eastern Norway. An analysis of roughly 600 moose livers, combined with information such as carcass weights and ages, shows that Norway's southernmost herds are afflicted with kidney problems and osteoporosis. (Credit: iStockphoto/Patrik Kiefer)

ScienceDaily (Nov. 7, 2010) Original article here
— Moose in southern Norway are in significantly worse health than those further north and in eastern Norway. An analysis of roughly 600 moose livers, combined with information such as carcass weights and ages, shows that Norway’s southernmost herds are afflicted with kidney problems and osteoporosis.

Marit Nordløkken, a PhD candidate at the Norwegian University of Science and Technology’s (NTNU) Department of Chemistry is investigating whether one of the factors behind these findings may be high concentrations of heavy metals.

Cadmium accumulation

Nordløkken’s analysis shows that there is enough cadmium in the moose organs from southern Norway that hunters should think twice before they eat large amounts of foods made with moose liver or kidneys, such as liver pate or kidney pie.

“Many heavy metals are stored in the liver and kidneys of animals and humans alike. I have found a great deal of cadmium in my analysis. Cadmium is not acutely toxic, but the amount in the body increases with age and can eventually cause health problems and disease,” Nordløkken says.

Geographical variation

Nordløkken has examined liver samples from about 600 animals. The samples are mainly supplied by hunters — primarly because it is rare that a moose will die of natural causes in a place where it can be found. She also collects information on carcass weight and age. This collection of information has enabled her to see that the size of the moose varies geographically, and that moose are larger the further north they live.

For example, the moose from the coasts of Nordland and Troms in northern Norway are much larger and heavier than their southern cousins, while moose from Trøndelag, in mid-Norway, are in the middle in terms of weight and size.

Nordløkken is able to determine the age of the moose by counting the rings in their teeth, much like biologists can age trees by counting annual tree rings. The oldest animal she has found to date is a cow that was 17-and-a-half years old.

Different diets

It has long been known that there are higher levels of air pollution and higher levels of heavy metals in southern Norway than in the rest of the country. This is due to atmospheric long-range transport from the rest of Europe where the heavy metals fall with acid rain.

The most severely affected areas are in West and East Agder counties and parts of Telemark county. This area is characterized by bedrock with granite and gneiss, both of which are not very good at neutralizing acid rain.

“It may also be important that the moose are living on different diets in different parts of the country. The department has another project that examines plants in the southern region and will provide further information about heavy metals in the plants that moose graze on,” say NTNU Professors Torunn Berg and Trond Peder Flaten, who along with Eiliv Steinnes are Nordløkken’s advisers.

The research is being conducted in collaboration with NINA, the Norwegian Institute for Nature Research, which monitors populations of deer.

Psychedelic Berlin art show hosts live reindeer, canaries and mice

November 7, 2010

5 Nov 10 – original article here


A fantastical exhibition by renowned artist Carsten Höller featuring live reindeer, canaries, mice and flies opened Friday at Berlin’s Hamburger Bahnhof contemporary art museum. “Soma” also offers the chance for a limited number of guests to overnight in a bed suspended above the animals for €1,000.

Höller’s exhibition directs the real-life quest to rediscover the ingredient of a mythical drink into the realm of art, the museum says.

The artist was inspired by a verse in the ancient Hindu text, the Rigveda, which reads: “We have drunk of the soma; we have become immortal, we have seen the light; we have found the Gods.”

In the 20th century, philologists, ethnologists and botanists have tried to identify the main ingredient of the enlightening beverage, the ingredients of which were lost over the years, the museum said in a statement.

But in 1968, American banker and hobby mycologist Gordon R. Wasson made the highly-disputed suggestion that the red and white poisonous fly Amanita mushroom may have been the ingredient, and that it may have been absorbed through the urine of reindeer, which eat the plant as part of their natural diet.

With this in mind, Belgian-born Höller, who studied agricultural sciences, has created a massive dual-sided “experiment.” Here 12 reindeer and other animals exist in two halves of the museum’s large hall – one side reflective of the “normal world,” and the other a scene from the psychedelic “realm of soma.”

“It’s about pondering,” he said on Wednesday.

The reindeer, brought to Berlin from Brandenburg’s Uckermark region, are reportedly relaxed and accustomed to human contact.

Other parts of the exhibition include mushroom sculptures and the limited possibility for visitors to spend the night alone in the museum with the live animals. Almost all of the available nights have already been purchased, the museum reported.

Each week the museum will hold a lottery drawing for one free overnight stay, though.

Stockholm-based Höller was born in 1961 in Brussels. He is best known for his 2006 work “Test Site” at London’s Tate Modern.

“Soma” runs from November 5, 2010 to February 6, 2011.

The Local/DPA/ka 

External link: More information here (in English) »

 

Pouches, pockets and sacs in the heads, necks and chests of mammals, part IV: reindeer and a whole slew of others

October 31, 2010

Reposted from the science blog of Darren Naish

I really must get this series on pouches, sacs and pockets finished. Last time, we looked at baleen whales (and then I got distracted by Caperea): in these animals, a large, inflatable laryngeal sac is used in producing loud, resonating noises (though roles in gas storage or the mechanics of exhalation have also been suggested).

Caribou_Karen-Laubenstein-USFWS-wikipedia-Oct-2010.jpg

Another ventrally located laryngeal sac is present in the Reindeer Rangifer tarandus [photo above, by Karen Laubenstein, from wikipedia, shows an Alaskan reindeer with wonderfully elaborate antlers]. The sac originates from the trachea close to the epiglottis, is present in both sexes (though is much larger in males, reaching 4000 cubic cm when inflated), and can extend asymmetrically either along the left or right side of the neck (Frey et al. 2007).

Rangifer-call-posture-Frey-et-al-2007-Oct-2010.jpg

During the rut, males adopt a characteristic posture where the head and neck are kept low and the throat is extended [shown here, from Frey et al. (2007)]. Because the air sac is seen to inflate and deflate as the deer calls, an acoustic role for the sac is obvious (the noises made by calling reindeer are difficult to describe: they make hoarse, repetitive guttural noises).

Exactly what effect the throat sac has on the sounds generated in the larynx is unclear. One suggestion is that the sac augments the acoustic output of the vocal tract, such that the resulting noise combines output from the mouth and nose with output from the sac, emitted via the soft tissues of the neck. In other words, the sac ‘filters’ the sounds produced in the vocal tract (in acoustics, a filter is “a resonator that absorbs energy at certain resonance frequencies” (Freyet al. 2007, p. 151)). Because displaying males approach females broad-side in what’s been called a ‘broadside acoustic display’, it appears likely that the sounds generated by these deer mostly emanate sideways.

Other acts of acoustic weirdness in Cervidae

The evolution of this remarkable laryngeal structure is made all the more, err, remarkable by the fact that it’s (so far as we know) completely novel within Cervidae, this despite the fact that other deer lineages have evolved profound modifications to enhance their calls [calling male Red deer shown below, image by Bill Ebbesen, from wikipedia. That lump in the throat corresponds to a highly mobile larynx that descends way down in the neck during vocalisation. Read on].

Red_deer_stag_2009_Bill-Ebbesen-Denmark-wikipedia-Oct-2010.jpg

As we’ve seen before, Red deer Cervus elaphus and Fallow deer Dama dama use laryngeal retractors and an elastic thyrohyoid linkage to pull the larynx down toward the chest and thereby decrease the formant frequencies of their calls (Fitch & Reby 2001, McElligott et al. 2006) (and formant frequencies are known to correlate with female preference and mating success in both Red and Fallow deer: see Charlton et al. (2007), Vannoni & McElligott (2008) and Reby et al. (2010). Incidentally, it’s probably true to say – as some have – that the vocal behaviour of Red deer has been more studied than that of any other mammal outside of Primates). Wapiti C. canadensis retract the larynx markedly as well (and I follow Geist (1999) and Groves (2005) in regarding the Wapiti as a separate species from Red deer*). Phylogenies show that Red deer and Wapiti belong to a disparate lineage relative to Fallow deer (e.g., Pitra et al. 2004): even if Cervus and Dama are sister-taxa, there are still numerous taxa in the Cervus clade that lack the laryngeal structures seen in the C. elaphusC. canadensis clade, and seen in D. dama. Their similar laryngeal anatomies must therefore have evolved convergently.

* Some other deer traditionally included in C. elephus also deserve to be recognised as separate species: I will avoid discussing this mess for now and point the interested reader to Pitra et al. (2004) and Groves (2005).

Similar elastic structures are absent in reindeer: there’s no indication that they can move the larynx in the same way.

Peculiar noises are also made by some other large deer, but in this case I’m not talking about vocal noises; White-lipped deer Przewalskium albirostre, Père David’s deer Elaphurus davidianus, Red deer, Wapiti and Reindeer all produce clicking or cracking noises in their joints as they walk (McCullough 1969, Thomas & Toweill 1982, Geist 1999). Red deer only seem to produce the cracking noise in the forelimbs, while Reindeer at least produce cracking in both fore- and hindlimbs.

We looked some time ago at joint-clicking in eland: remarkably, the noises made by the joints of these antelopes form part of their dominance displays (Bro-Jørgsen & Dabelsteen 2008). Could the same be true of the joint-clicking deer? A popular idea is that the clicking noises provide information on the whereabouts of other herd members, and also on the approach of possible danger. I don’t know if anyone has studied this (though humans who hunt deer have certainly been very interested in it) – let me know.

One more interesting thing to note on deer and acoustics: it has been suggested that the enormous palmate antlers of Moose Alces alces may work as parabolic reflectors that help collect sound (Bubenik & Bubenik 2008) [spectacular Alaskan moose shown below; photo by Donna Dewhurst, from wikipedia. Note the profound asymmetry in the antlers… fluctuating asymmetry, another subject I must cover some time].

Moose-Donna-Dewhurst-Alaska-wikipedia-Oct-2010.jpg

Moose ears are large and sensitive, but these authors showed that a moose can increase the acoustic pressure in its ears by about 19% if it points the ears towards the antlers rather than toward the sound source. I would assume that this effect is incidental given that the antlers are still shed annually, mostly play a role in sexual combat and display, and are absent in females (one would assume that they would be retained year-round, and be present in females, if an acoustic role provided a selective advantage). However, moose that inhabit Alaskan tundra environments have the biggest antlers, and this is a habitat where sound travels furthest. Then again, visual signals would also travel furthest, so – as usual – things are not clear-cut.

Reindeer are ‘grotesque giants’

Having shown that Reindeer are unexpectedly weird by virtue of their laryngeal sacs, it’s only right to say that they’re really interesting for lots of other reasons: with their elaborate antlers (proportionally, the biggest of any deer), cursorial specialisations, large body size (second largest New World deer), long neck manes, large fat stores and highly peculiar, complex pigmentation (they have capes, rump patches, lateral stripes, forehead patches, eye rings and ‘socks’*), they’re flamboyant animals that can be regarded as ‘extreme’ members of their group (incidentally, the neck mane might be a visual signal linked to the neck sac) [Rangifer and Alces are shown in the diagram below as extreme members of the mostly New World deer clade that includes brockets, roe deer, reindeer and moose (from Geist (1999))].

New-World-deer-Geist-1999-Oct-2010.jpg

Geist (1999) referred to animals of this sort as ‘grotesque giants’ and noted that they tend to have evolved in cold, harsh Ice Age environments. Gould used the term ‘asynchronous hypermorphs’ for the same set of species. Other examples – according to Geist – include moose, wapiti, muskox, woolly rhinos, short-faced bears and humans.

* Pigmentation patterns are highly variable in reindeer, with some forms being far more elaborately patterned than others. Eurasian tundra reindeer are the most elaborate.

More laryngeal bullae than you can shake a stick at

Frey-et-al-2007-laryngeal-bulla-diversity-Oct-2010.jpg

So far in this series of articles, we’ve looked at primates, baleen whales and reindeer. But these are far from the only mammals with laryngeal diverticula located on the midline of the throat: small sac-like structures located on the ventral surface are also present in opossums (Didelphis), quolls (Dasyurus), some phalangers (Trichosurusand Phalanger), swamp wallabies (Wallabia), hedgehogs (Erinaceus), squirrels (Sciurus), marmots (Marmota), water voles (Arvicola), tapirs (Tapirus), horses (Equus), boar (Sus), eland (Tragelaphus), saiga (Saiga), takin (Budorcas), some bears (Ursus), wolves (Canis lupus), southern sea lions (Otaria) and various others (see Frey et al. (2007) for a complete list: their table, with adjacent diagrams showing laryngeal diverticula position, is shown here).

In some taxa, these structures are associated with enlarged hyoid bullae (like those looked at previously in apes and howler monkeys), but in others they are not. And in some of these mammals, these diverticula are paired; in others they are single. In the marsupials with a laryngeal diverticulum, and also in eland, saiga and takin, the structures are housed inside an inflated bulla formed from the thyroid cartilage (and are thus contained within the larynx). As yet, the role that these many diverticula might play in vocalising and other aspects of behaviour has been little investigated for most of the species concerned. Roland Frey and his colleagues have, however, been publishing some great studies on the laryngeal anatomy and vocalisation in such species as muskox, takin and weird gazelles. More soon!

For the previous articles on pouches, pockets and sacs in mammal heads, necks and chests, see…

And for previous Tet Zoo articles on deer, see…

Refs – –

Bro-Jørgsen, J. & Dabelsteen, T. 2008. Knee-clicks and visual traits indicate fighting ability in eland antelopes: multiple messages and back-up signals. BMC Biology 2008, 6: 47 doi:10.1186/1741-7007-6-47

Bubenik, G. A. & Bubenik, P. G. 2008. Palmated antlers of moose may serve as a parabolic reflector of sounds. European Journal of Wildlife Research 54, 533-535.

Charlton, B., Reby, D. & McComb, K. 2007. Female red deer prefer the roars of larger males.Biology Letters 3, 382-385.

Fitch, W. T. & Reby, D. 2001. The descended larynx is not uniquely human. Proceedings of the Royal Society of London B 268, 1669-1675.

Frey, R., Gebler, A., Fritsch, G., Nygrén, K., & Weissengruber, G. E. (2007). Nordic rattle – the hoarse phonation and the inflatable laryngeal air sac of reindeer (Rangifer tarandus)Journal of Anatomy, 210, 131-159

Geist, V. 1999. Deer of the World. Swan Hill Press, Shrewsbury.

Groves, C. 2005. The genus Cervus in eastern Eurasia. European Journal of Wildlife Research52, 14-22.

McCullough, D. R. 1969. The Tule Elk. Its History, Behavior and Ecology. University of California Press, Berkeley.

McElligott, A. G., Birrer, M. & Vannoni, E. 2006. Retraction of the mobile descended larynx during groaning enables fallow bucks (Dama dama) to lower their formant frequencies.Journal of Zoology 270, 340-345.

Pitra, C., Fickel, J., Meijaard, E. & Groves, C. 2004. Evolution and phylogeny of old world deer. Molecular Phylogenetics and Evolution 33, 880-895.

Reby, D., Charlton, B., Locatelli, Y. & McComb K. 2010. Oestrous red deer hinds prefer male roars with higher fundamental frequencies. Proceedings of the Royal Society of London B 277, 2747-2753.

Thomas, D. C. & Toweill, D. E. 1982. The Elk of North America; Ecology and Management. Stackpole Books, Harrisburg, PA.

Vannoni, E. & McElligott, A. G. 2008. Low frequency groans indicate larger and more dominant Fallow deer (Dama dama) males. PLoS ONE 3(9): e3113. doi:10.1371/journal.pone.0003113