When engineers at Rice Lake Weighing Systems designed the RoughDeck® series of floor scales, they set out to build something that could withstand demanding industrial abuse. Reckless forklift driving, incautious loading, and other common mistreatment scenarios were taken into account and precautions were built into the design, including welding a full 6 lb structural channel frame to a durable steel deck for increased rigidity.

Those engineers probably didn't think a RoughDeck would be in a situation where a 486-pound silverback gorilla climbs to the highest point it can find and rockets himself down on the scale in a display of dominance. Reminiscent of a scene out of King Kong, this is one of the ways silverback gorillas at the Denver Zoo test the limits of Rice Lake's RoughDeck.

The zoo is currently undergoing construction efforts to increase the quality of life for its impressive variety of animals. The exhibits are being supersized and re-planned to provide a more natural, open-air environment and minimize animal stress. New exhibits like the Asian Tropics are being planned. With these new and improved exhibits, scales are needed. Rice Lake RoughDecks are often being utilized for the medium- to large-sized animals including primates and lions and hyenas.

Why is it important to weigh animals at the zoo? The casual zoo visitor might think animal care is as simple as throwing a juicy T-bone steak into the exhibit once a day and the rest will take care of itself. There is much more science that goes into ensuring animal health. BJ Schoeberl, curator of primates and carnivores at the Denver Zoo, explains "Just like in humans, monitoring weight helps in assessing proper diet amounts and health. We always try to keep our animals at optimum weights for their health and wellbeing. By monitoring weight, we can adjust diets to keep them at target body conditions."

It turns out that animals are very similar to humans in weight fluctuations - age, disease, pregnancy and change in activity levels are all contributing factors to changes in weight. The animals' diet is constantly being monitored and adjusted to compensate for these fluctuations. Exercise is also promoted by placing props, such as furniture-like platforms, ropes, and other enrichment items to encourage movement and make them "work" for food. Imagine if there were similar challenges for humans. Before getting one's dinner, one would have to climb and swing from ropes rather than slowly inch one's car through a drive-thru. Instead of a bacon double cheeseburger, one would be rewarded with healthy treats tailored to one's current weight. Maybe the zoo is onto something!

If the health of an animal deteriorates because something is wrong (rather than natural factors such as old age), there is no way for them to vocalize how they feel. No Dr. Dolittle exists to translate between animals and humans. If they are depressed, anxious or sick, eating habits are often the first to change. This is their way of sending a message. Obtaining accurate weight readings are the most effective means of reading these messages this side of an animal psychic. The weights are then used to determine daily food intake and, if needed, proper medication dosage. Getting that weighment is sometimes a challenge in itself.

Primates are smart.very smart. One look into their expressive eyes and you can tell there is more going on behind them than in most other animals. With proper incentive (applesauce, sugar-free juice, pudding, gelatin dessert, raisins, nuts, grapes, or uncooked pasta), primates can be trained to do almost anything, including standing on a scale. While a giant handful of uncooked pasta might not seem like the most appealing treat, if your typical daily diet consisted of a mixture of 18 pounds of primate chow and leafy greens, those crunchy macaroni noodles would suddenly look pretty good and you might be willing to stand on a scale for a few seconds to get a snack.

While their intelligence makes training easier, it is also a double-edged sword. Because the animals are so curious, they often want to monkey with the scale.

They see something interesting and want to investigate. Powerful gorilla fingers can easily turn bolts. Primates' social awareness introduces another unique challenge. In the animal world, position in one's pack is an important element of who one is. Especially for a leader, it is important to demonstrate alpha skills and weighing time provides the perfect opportunity to show off. "Displays are a big part of male gorilla behavior," said BJ Schoeberl. "During display behavior, they are usually interested in making a big visual impression on whomever is watching, so the louder and bigger the actions are, the more impressive the display. They jump, bang and hit objects, including cage furniture. Sometimes the scale takes the brunt of these displays."

One look at a silverback gorilla and it's clear these are strong animals. Their bodies are reminiscent of a post-year-2000 Barry Bonds (plus a lot of hair), with muscles on top of muscles. One can only imagine the force being displaced on the surface of an 18" x 24" RoughDeck during an intimidating display of bashing, throwing, and jumping. Even though the heaviest gorilla is just shy of 500 pounds, 2200-pound load cells have been installed to help withstand the abuse. "Rice Lake load cells hold up incredibly well," said Chad Stedman, general manager of Colorado Scale Center, who installed and maintains the zoo's Rice Lake equipment. "Even with the occasional gorilla climbing a ladder and jumping down on the scale, the RoughDeck and load cells have held up. Primates have even tried to pick up and bend the scale. The zoo has been very happy. Before we went to Rice Lake load cells, they were going through load cells pretty quickly. The performance has really moved the zoo over to Rice Lake. Performance is proof."

Of all the scales at the zoo (all animals are weighed at regular intervals), many require routine maintenance or frequent replacement. The Rice Lake RoughDecks are under some of the most abusive conditions yet require only occasional maintenance.

A longtime animal lover and regular zoo visitor even before the installations, Chad relished the opportunity to install Rice Lake scales at the Denver Zoo. "It was exciting to see areas that are usually off-limits to visitors," Chad said. "I was happy to install the RoughDecks for them because I knew they would hold up better than any other scale." Animal weighments normally are done in a special room where the animals are not visually exposed. This helps reduce anxiety on the more social species like primates. However, some species are
not as sensitive to onlookers.

The zoo's Predator Ridge exhibit is a world-class, large, open-air environment mimicking a natural setting for the pride of lions who live there. Ten-foot-tall mounds were constructed so the lions can be "king of the hill" and get a lay of the land. Selected rocks are electronically wired for heat, providing a premiere napping locale. Nearby animals are rotated, stimulating the lions' olfactory sense just as it would in the wild. Making the animals feel more at home is an effort to decrease the stress of captivity and increase their overall health.
The weekly lion weighing has been transformed into a public experience because, unlike the primates, cats don't seem to mind human observation.

A special apparatus was created for this task that uses Rice Lake's IQ plus® 355 digital weight indicator and a RoughDeck floor scale. "The lions are trained to get on the scale and perform other behaviors for the keepers as part of the public demonstration," said BJ Schoeberl. "This is one of the most popular demonstrations at the zoo!" The IQ plus 355 indicator is an ideal choice because its large bright LED display makes it easy for spectators to see the lion's weight (approximately 430 pounds for the males and 285 pounds for the females). Its digital filtering capability also allows for an accurate weight reading despite movement on the scale.

Going Green

As the Denver Zoo is planning for the future with their exhibit remodeling and additions, another important green project is underway as well.

With the increased concerns about global climate change and the role that years of industrial development has played in increasing pollution, the zoo, like most organizations, is searching for environmentally friendly solutions. One of the main contributors to increasing pollution is the overwhelming use of plastic. It's cheap, relatively strong, and moldable to virtually any shape; however, plastic doesn't biodegrade. Instead, it disintegrates into increasingly smaller particles. So, where do these plastic particles end up? Often, it's in the ocean.

Right now, there is an area of the Pacific Ocean between the coast of California and Hawaii that serves as a pooling station for non-biodegradable garbage from both the U.S. and Japan. The North Pacific Gyre collects this trash through a pattern of swirling ocean currents and deposits it in a central location known as "Garbage Island," which has now blossomed to a size twice that of Texas. Unfortunately, the marine life in this area has a better chance of eating plastic particles than plankton. When that same marine life ends up on our dinner plates, we ingest chemicals thought to cause disease and sterility-not exactly what we had in mind for a main course.

To stop the damaging effects on the environment and, in turn, our health, the Denver Zoo is doing its part. It has eliminated plastic and Styrofoam® containers in its cafeteria and concession locations throughout the zoo. The garbage receptacles are color-coded by material for recycling purposes. The zoo is also going beyond a typical recycling plan by mixing specific ingredients of human garbage and animal waste to create fuel through a gasification process.

Paul Quick, who is working on the gasification project, explains, "When the color-coded containers are picked up on a Jeep®, they're weighed and identified so we know how much of each material is being acquired. We use a mix of about 50-50 between animal waste and compostable materials. Then we shred and process it and reduce the moisture content to 15 or 20% so everything has a similar density. The downdraft gasification process is a controlled oxygen conversion, so instead of burning the waste, it is being forced to chemically break down inside of a chamber.

"When it breaks down, the waste gives off gases such as methane, hydrogen, and carbon monoxide. We then combust those gases in a combustion engine and capture the energy in a generator. In this process, a lot of heat is generated; 60 percent results in heat and 30 percent results in electricity, and only 10 percent is lost. Most combustion engines are only 20 to 25 percent efficient."

For the new 10-acre Asian Tropics area that will feature abundant water exhibits, the waste-powered generator will run water circulation pumps, heat the buildings, and provide hot pools for the elephants. "By controlling which materials enter the gasification process," Paul said, "we're able to achieve a more efficient output." Monitoring the quantity of each ingredient entering the process is all done by weight, and Rice Lake load cells are being used for their durability.

The zoo has developed a customized press to extract moisture from animal waste, leaving a dry and combustible product. The waste is loaded into the press and a lever is pulled downward. As the waste is compacted, the moisture is removed. Four RL9000 TWM Series stainless steel weigh modules are mounted in this press to give accurate data on how much usable waste is being collected.

Repurposing the zoo's daily waste output into electricity and heat is an ideal example of how we can reduce our impact on the environment. Using sustainable resources and creating plans that reuse waste may be the key to preventing Garbage Island from becoming Garbage Continent.