No.  Okay, wait, that was hasty.

• A wildlife tour in Yellowstone will cost $400 for a family of four
• The tour leaves at  unGodly-o’clock and returns 8 hours later
• You will have a 50/50 chance of being on the wildlife side of the bus
• The bus has other people

This is what a bear looks like in the wild from the roadside.  This is through binoculars.

Contrast this with 8 hours of hiking

• Cost, nothing
• Leave after breakfast
• Hike eight hours and return to your cabin ready to sleep
• Both sides of a trail have a view
• Get to know your kids instead of strangers

We clocked 28-1/2 hours of hiking with our teenagers, Gage and Cole, in five days of hiking at Yellowstone.  We learned that we were more afraid of buffalo than seeing a bear, that my husband, Brad, has no idea how far 100 feet is.  We learned that Gage is the best judge of 100 feet and Cole is the best photographer.  A rented camera lens weighs 8 pounds, same as a gallon of water.

This is what wildlife looks like from the trail.

So, now that I think about it, my answer is the same.  No, you do not need a tour in Yellowstone.  Get out and hike, get to know what 3-and-1/4 miles feels like.  Get to know your family.