Incorporating Plants into Animal Tours – Beyond the Birds & The Bees
Los Angeles Zoo and Botanical Gardens
The Los Angeles Zoo became The Los Angeles Zoo and Botanical Gardens two years ago. Many of the docents were less than enthused. Plants? You want us to start doing plants? I don’t have anything against plants. You can do plants, I am an animal person.
Deep down inside we all knew that plants had many redeeming ecological values. Plants were the first life to colonize the land on this planet; plant life constitutes more than 98% of the total biomass of the earth. We completely reliant upon plants to convert the carbon dioxide we inhale into oxygen. Interesting? True. But the subject simply didn’t turn many of us on.
Getting Started: Committees and Workshops
Although we had just been accredited as a Botanical Garden, due to budgetary constraints and a hiring freeze, we no longer had a Curator of Botany to give us a sense of direction. We had a terrific Horticulture Department, but it was concerned with the growth and maintenance of our plant collection, not teaching botany to docents. So we formed a Botany Committee, we had to learn about botany – the study of plants and their relationships to each other, not horticulture -how to grow them. Initially, the subject was overwhelming. We had to start from scratch, so we started searching for comprehensive books oh the subject, easier said then done.
Most plant books are designed for gardeners, with descriptions of the how and where to plant what. These books simply list plants by genus, as did our Horticulture Department, by the way. This means everything is listed alphabetically, by genus, HI Latin. They had nothing in common other than the first letter (or genus). Somewhat similar to having the animals listed alphabetically – boas, bobcats, bongos, then bonobos, followed by boobies – they had nothing in common – no interesting relationships or stories to tell. Finally we found a source, “Botanica” that included a comprehensive list of plant families and we got to work on fact sheets on a few plant families. We continued to search the shelves for the botanical equivalent of MacDonald’s “Encyclopedia of Mammals” in vain. (I even took an introduction to botany class at U.C.L.A.)
So now we have held a few workshops, we try to keep them simple, with illustrated talks concentrated on one group of plants at a time followed by tours. In all of these we have used the approach that a few interesting pieces of information will not only provide a foundation to build on but hopefully whet the appetite for docents to learn more. We have covered subjects from various angles: desert plants and their adaptations, another featured peas, beans and pods – the huge legume family. Our very first workshop focused on evolutionary beginnings, the ancient plants in our collection such as horsetails, ferns, cycads, gingkos and conifers. Our zoo is currently featuring an exhibit of mechanical dinosaurs, so in the frenzy of “dinomania” we dug out our old workshop notes and with a little further research we were able to compile a “Guide to Dinosaur Dining” for the docents.
But there is a lot more to plant and animal relationships than food, and being an animal person myself, this became my primary area of interest to cover in our workshops. This aspect always seemed to interest previously uninterested docents as well. But where to find a reliable resource with lots of information?
Enter David Attenborough to the rescue! Along with National Geographic, Sir David undoubtedly inspired many of us to further discovery of the natural world, and maybe to take those first steps to volunteer at our local zoos. Several years ago he did a series, and book, titled “The Private Life of Plants, A Natural History of Plant Behavior”. Behavior?
I had always thought that plants just sat there and grew, or not, but “behave”, as in animal behavior?? If anyone can make a subject interesting, David Attenborough certainly can. From his introduction:
“Plants can see. They can count, & communicate with one another. They are able to react to the slightest touch and to estimate time with extraordinary precision. A plant shoot kept in the dark will creep toward a single chink of light. The plant can see.
Hedgerow flowers facing west at sunset, turn during the night to face east to catch the dawn sun, and will continue to make such movements even when kept under uniform lighting for days on end. They can estimate time. The Venus flytrap closes when its trigger hair is touched not once, but twice. It can count.”
He had me already, and he hadn’t even mentioned animals.
Plant and Animal Relationships
Don’t ever forget that the plants came first, and in many ways are much more successful organisms than animals. They can thrive in places where no animal can exist for any length of time. They grow much larger than any animal and they can live far longer. All animals are totally dependent upon plants, even the most determined of carnivores, eat plants, if not first-hand, then at second, third, or fourth.
You probably have many herbivorous animals in your zoo, so you refer to plants on your tours already. What do they eat? Leaves & branches, fruit and flowers …but which branches of what tree, which fruit, which flowers? Ask your keepers which plants they use for browse, for enrichment, or for nesting material, and then you can point these out. If probably talk about pandas who eat the shoots and leaves of bamboo.
Koalas have dietary requirements limited to the fresh leaves of certain species of eucalyptus. When our koalas arrived from Melbourne they were accompanied by a keeper who was amazed that we actually had some of those very species of eucalyptus growing within our zoo grounds. The irony is that back in Australia they had to drive 20 miles from the city one-way in order to find the appropriate eucalyptus to use for browse.
We have an enrichment “Garden of Beastly Delights” on zoo grounds where we grow a assortment of herbs along with nasturtiums, corn and other edibles as well as an off site “Gorilla Garden” where we grow the gorilla’s favorite, roses, along with assorted other munchies.
From the point of view of a plant, animals that eat them are predators (or parasites). Plants have evolved many strategies to use animals, ranging from the lure of sweet nectar to offerings of colorful, nutritious fruit as rewards for as –
sisting in pollination and seed dispersal.
All kangaroo paw plants are pollinated by birds, but with variations. Some species are only a few inches, so they high point their flowers downwards so that a bird can hop along the ground and simply reach up with its beak to sip nectar without any difficulty. But the taller species of kangaroo paws have flowers that are beyond the reach of a bird on the ground, their stems must be much stronger and stout than seem necessary to support blossoms, because they have to carry the full weight of the pollinating bird, in this case a tawny-crowned honey-eater.
Birds use plants in many interesting ways. Many birds protect themselves, and their young from any number of possible parasites and infections by carefully selecting foliage for lining their nests. House sparrows near Calcutta, India line their nests with leaves of the Margosa tree while the local people who use these same leaves to protect their clothes from insect damage. European starlings use wild carrot & fleabane, among others, for the same reason.
Are you aware that some reptilians are pollinators and seed dispersers? In New Zealand, geckos regularly visit the of the flowers of native flax to sip their nectar, meanwhile collecting pollen on their throats and chins, and proceed to pollinate the next plant it visits. Iguanas are unusual among reptiles because they are herbivorous as adults. They eat a variety if vegetation, including seeds, and since their teeth are not designed for chewing effectively, some of the seeds pass through their digestive tracts still capable of germinating. ‘Iguanas are not only seed predators; they are actually important seed dispersers!
During hot summer days very few animals of any kind are active, so cacti open their flowers at dusk and shut them again in the morning. Night-blooming cacti have pungent scent and pale blossoms, which reflect the moonlight in order to attract bats as pollinators. Many cacti even arrange their flowering season to coincide with bat migration; their abundant nectar provides an invaluable pit stop for the lengthy journey from Mexico to the southwestern U.S.
But there are other mammalian pollinators – marsupials ranging from tiny possums to American opossums. Pollinating primates include bush babies, lemurs, tamarins, capuchins & spider monkeys to name a few. Don’t forget that animals that eat fruit and seeds are probably also seed dispersers. Further information on unusual pollinators may be found in the book “The Forgotten Pollinators” and the web site with the same name. Web searches on “seed dispersal”, “pollinators” are guaranteed to provide rewarding examples.
Passage through an animal’s gut is essential for some seeds. The umbrella shape of acacia is common on the plains of East Africa, their seeds are enclosed in tough, twisted pods but many animals relish them because they are rich in protein. The seeds that remain on the ground uneaten seldom, if ever, germinate, but those that are swallowed with the pods and then pass through an animal’s digestive system nearly always do. Shortly after the acacia tree sheds its pods, large numbers of a particular species of beetle fly in, pierce the pods with their sharp ovipositors and proceed to deposit their eggs. The eggs hatch rapidly, and the tiny grubs then proceed to feed on the seeds.
However, if the pods are eaten by a large animal such as an elephant… The elephant grinds up the pods with its teeth, but many of the seeds remain unharmed and are swallowed with the mash. All of the beetle eggs are killed by the digestive juices in the elephant’s stomach. So when these seeds “return to the outside world” along with a nice supply of fertilizer, they have been inadvertently freed from their insect pests by the elephant.
Plants are rooted to the spot and possess neither nerves nor muscles but plants may exhibit some dramatic behaviors in defense of themselves, similar to that of animals. So, a bit more about acacias, they are well protected by their thorns, but along with several other species of trees, they have a secondary line of defense · distasteful chemicals. When an eland or a kudu browses on the leaves, over – browsing stimulates production of a form of tannin to make them indigestible and to actually impede further digestion, which may be injurious to the animal. The chewed leaves remaining on these trees release substances, which drift into the air to stimulate others of the same species to begin to protect themselves. When an antelope finds that the tree it first attacked is no longer fit to eat it moves away. But it has to move some distance, for trees as far as 50 yards away have been forewarned by the drifting gas, and thus forearmed.
Giraffes are perfect animals to use to discuss the adaptations some animals have to deal with obtaining, and digesting food. Lengthy tongues and long necks enable them to reach leaves no other animal can. They have ever -growing teeth designed for grinding and ruminating stomachs enable them to obtain more nutrition from their food. Like many other animals, giraffes eat acacia, and they have figured out how to beat the acacia warning system! Somehow giraffes understand that the attack alert only drifts downwind – therefore they start browsing downwind and work their way upwind to the plants that have yet to receive the message.
And there are examples of plants being used by thornbugs to transmit messages to other thornbugs.
Recently it is been discovered that some plants are capable of raising their temperature to attract pollinating insects and tempt them to linger longer than normal.
Many years ago I saved an interesting article with a great title, “Plants of the Apes”. It described how many animals “self-medicate” by eating certain foods or other natural substances. At first this sounds a bit far-fetched, but think about it – has your veterinarian ever been alarmed when told him that your dog or cat had been munching on grass?
Perhaps you have even purchased a plant marketed in grocery stores specifically for use by your cat.
Several years ago a few primatologists started observing unusual feeding behaviors among the chimpanzees in different study locations, in Africa. Some chimpanzees that seemed in poor health, behaved in a depressed or a sickly manner, tended to separate themselves from the group and forage on plants they normally avoided. The animals folded bristly leaves and grimaced when they swallowed them, obviously these were»not normal food choices. Within a few days the animals were acting normally. The researchers later discovered that these bristly leaves had acted with a “Velcro effect” ridding the lower intestines of parasitic worms. Many species of primates have been observed seeking and eating leaves for what are believed to be medicinal purposes. Other studies are concerned with the trees that chimpanzees select for their nightly sleeping nests, do the leaves of these trees contain natural insecticides? Many researchers have interesting examples from a wide range of animals self-medicat ing, the field is called zoopharmacognosy. “Wild Health” is an interesting book on this subject.
One more story about plant defense. When some leaves are nibbled by a foraging insect, they produce chemicals that give the bug indigestion but it may also make it feel falsely stated. We have already learned that an injured leaf may signal leaves on other plants to muscle up their chemical defenses before the bad guys arrive. Corn &’bean plants can even summon mercenaries – when some species of caterpillars munch their leaves, the plants emit chemicals that attract wasps, parasitic wasps. The wasps (hen lay eggs in the caterpillars, & the developing wasp larvae proceed to eat their caterpillar hosts. The plant has reciprocated (revenge is sweet, maybe the plant is happy?) Revenge, another candidate for Sir David’s list?
We can approach plants in many ways. Do not be intimidated; you do not need to know it all. As docents, we may compare of many similarities between plants and animals:
both have defense systems of thorns and spines, think echidnas and porcupines cryptic coloration / camouflage
deceit are alive and well in both kingdoms flowers and animals both use scent to attract a mate, or a facilitator / pollinator strangler figs constrict much like boas and pythons there are many carnivorous plants, just as there are many carnivorous animals toxins may be compared to the venom of many snakes
Pick just one tree, or plant, and learn all about it. An oak for example, provides food and shelter for many animals from squirrels to blue jays. Do you know what your state tree is, or your state flower? These could be your beginning.
Students on your tours have probably studied how Native Americans used plants m many diverse ways – from baskets to herbal medicines. “My Favorite Tree”, a children’s book, is a painless way to get started.
We have only had time to merely scratch the surface, there is so much to tell and so little time. Much of it may be new to us, but not to the plants, or to the animals. There many amazing plants, and other fascinating plant and animal relationships to discover.
Now let’s have a discussion of ways you have incorporated plants into tours in your zoo.
Bibliography for Beginners:
Botanica by R. G. Turner Jr., 1999, Blames and Noble
Botany in a Day, Thomas J. Elpels, 4th Edition, HOPS Press, Pony, Montana
Botany of Desire, A Plant’s Eye View of the World, by Michael Pollan, 2001, Random House,
Private Lives of Plants by David Attenborough, 1995, Princeton University Press
My Favorite Tree, by Diane Iverson, 1999, Dawn Publications, Nevada City, CA
Sex in Your Garden by Angela Overy, 1997, Fulcrum Publishing, Golden, Colorado
The Forgotten Pollinators by Stephen L. Buchmann and Gary Paul Nabhan, 1995, Island Press
Wild Health by Cindy Engel, 2002, Houghton Mifflin Company
Ecological Relationships of Plants and Animals by Henry F. Howe & Lynn C. Westley, 1988, Oxford University