Critter Chronicles: A Symbiote

I've decided that, for the purposes of this blog, "critter" includes anything alive -- animals, plants, and those that are somewhere in between.

While waiting for buses yesterday, I was noticing the lichenbs growing on trees by the bust stops. One in particular, a locust, had three different types of lichens growing on it, one green, one gray, and a couple of small patches of golden orange.

And what, exactly, is lichen? you may ask. From the U.S. Forest Service:

Lichens are a complex life form that is a symbiotic partnership of two separate organisms, a fungus and an alga. The dominant partner is the fungus, which gives the lichen the majority of its characteristics, from its thallus shape to its fruiting bodies. The alga can be either a green alga or a blue-green alga, otherwise known as cyanobacteria. Many lichens will have both types of algae.

There are about 3,600 species of lichen, and they take various forms -- low-growing, crusty-looking habits, branching, filamentous, you name it. The Field Museum a while back, had a small exhibition on lichens that was very interesting. One of the examples was the door from an old pickup truck that was covered in lichen. They'll grow pretty much anywhere -- I've seen them on trees, on rocks, on old scrap metal that's been lying outside -- all sorts of places.

Fascinating critters.

Review: Bernd Heinrich: Mind of the Raven

Another Epinions piece that almost went down the memory hole. (I just spent ten minutes looking for one that did. Grr. . . .) At any rate, in case you were wondering about ravens, here you are.

Bernd Heinrich is a researcher and professor of biology at the University of Vermont. He is also the author of several books, including Bumblebee Economics, which was nominated for a National Book Award, and is a winner of the John Burroughs Medal for Natural History Writing. In his Preface to Mind of the Raven he recounts the origins of his focus on ravens and their behavior – for those who know and enjoy the raven's place in mythology and folklore, it seems only fitting that it started with a dream.

Among the questions Heinrich posed for himself was one that is very basic and not strictly scientific: why is the raven, of all birds, credited with being extraordinarily intelligent and, in many respects, almost human? Heinrich's studies over the next few years focused on the social life of the raven: mating, family life, group behavior, dominance patterns, communication (a very rich area), and a host of other areas and sub-areas. Heinrich has supplemented his own research, from studies carried out in Maine and Vermont, with information from other researchers in the U.S., Canada, and Europe. The result is a fascinating picture of a remarkable bird.

Ravens, like other members of the crow family, are opportunistic feeders, largely scavengers (although Heinrich cites observations of ravens trout-fishing in Yellowstone Park, which I have done myself, although not quite the way they did it). Foraging and food-sharing lead to complex social behaviors, in that, while ravens are largely solitary, there exist associational networks among ravens that determine who will be allowed to share a find and when. There are also observations of ravens flushing game for other predators and then attempting to steal the kill – they come by the "thief" epithet honestly, it would seem.

As one might expect, communication is highly developed, and apparently has some fluidity. They also play. Ravens exhibit complex behaviors, such as caching food, defending caches, deception, and raiding other ravens' caches, that necessarily demand some learning and some freedom of action. Heinrich includes comments on these activities as well as a chapter entitled "Morality, Tolerance, and Cooperation" which includes his observations on how tolerance develops between a group of ravens and a newcomer.

While his approach to his subject leaves Heinrich scope for philosophical rumination, he does take off from hard fact. Although he does not bring in the raven's role in folklore to any great extent, one can easily see how its reputation was earned – thief, trickster, fighter – it's easy to see how a raven's croak could be taken for an omen.

There are places where I would have preferred less rumination and more fact, although the wealth of information itself can give the reader pause. On the whole, for anyone interested in ravens and their behavior, it is a valuable book, although not one that makes an easily used reference.

(HarperCollins, 2007)