Confusion from Tacoma to Tundra Wheels

I have a 2015 Toyota Tacoma and it has a 6 bolt pattern on the wheels. This weekend my brother-in-law visited in his 2011 Tundra. I was shocked that his wheels were only a 5 bolt pattern. What is up with that?

I don't understand why a bigger, heavier duty truck would have the same size wheels (both were 18") but the smaller Tacoma had a 6 bolt pattern. Maybe I am incorrectly assuming that the more bolts holding the wheel on is stronger. After all my 3500 HD Silverado had an 8 bolt pattern.

TIA

 

The Tundra(07+) uses larger studs and on a slightly larger bolt circle. Tacoma is 6 on 5.5"(6x139.7) and the Tundra runs 5x150mm.