Second part to the question before this.
Wildlife: What to Do
Once in a blue moon, you may encounter a wild animal in Yellowstone Park. Don't let curiosity kill the cat. Rule number one is to never approach the wildlife in the park. If you happen to encounter an animal on your adventures, there are a few important things to remember. These animals consider the park their home and may have babies nearby. You may seem like an intruder, and that is just the tip of the iceberg. Bison have injured more people in Yellowstone than any other animal. They are unpredictable and can run three times faster than humans. Other common animals in the park are bears. If you encounter a bear, remain calm, and try to appear nonthreatening. First, do not make direct eye contact with the bear. Next, speak to it in a calm voice so that it knows you are human. Then, leave the grounds calmly and slowly, never turning your back to the bear. Finally, if you have bear spray, remove the safety lock, and keep it on hand in case of an emergency. Ultimately, the safest way to view wildlife is from the inside of a vehicle.
Water and Geysers
Water plays an incredible role in the ecosystems found in Yellowstone National Park and the surrounding areas. The water that flows through the park is a vital national resource. Precipitation in the mountains flows through networks of streams and rivers to provide important moisture and habitats to plants and wildlife. The park is home to the largest concentration of mammals in the lower 48 states, including more than 150 species of birds and six species of reptiles, all of whom rely on the fresh water.
Water drives the complex geothermal activity that occurs within the park. It fuels the largest collection of geysers on Earth. Precipitation and groundwater seep down into geothermal systems which is heated by the Yellowstone Volcano. This precipitation is heated and then rises to the surface in the form of hot springs and geysers. The most famous geyser in the park, Old Faithful, was the first to receive a name.
Old Faithful
More than 1 million eruptions have occurred at Old Faithful. On average, Old Faithful erupts once every half hour to two hours, and each eruption lasts 1.5−5 minutes in length. Some say that Old Faithful is slowing down after more than 100 years of eruptions. Eruptions occur by heated water rising toward the surface and being superheated due to the narrowness of the channels through which it travels. Ultimately, the temperatures force steam bubbles and boiling water to the top of the channel and cause the water to burst through. The eruption stops when the water basin is empty or when the entire system ejects enough water to cool down. Remember, getting too close to any of the hydrothermal features, such as Old Faithful or hot springs, can cause severe or even fatal burns. Scalding water lies under most of the thick, breakable ground surrounding these formations, so it is best to keep a safe distance.