I was treated to a special behind-the-scenes "Blogger" tour of the "Extreme Mammals" exhibit opening Saturday, April 3, at the California Academy of Sciences in Golden Gate Park.

But first a disclosure: I'm a big fan of the Cal. Academy of Sciences, I first joined in 1985, however, I miss the old building, it had far more content. I'm not at all impressed with the half-a-billion dollars spent on the new building. I don't care about the "living" roof -- I've got more living species in my fridge. And the high entrance fee of $25, makes it inaccessible to a lot of people, especially if you turn up with your family.

AND there is no geological exhibit! That used to be my favorite exhibit, the rocks and minerals, and gold. And no earthquake table. You used to be able stand on a platform that simulated a variety of earthquakes, while watching videos of real ones. We live in California, a seismically active region and with a rich history of minerals and metals. Yet in the new building now have a "rain forest" taking up so much space, an exhibit filled with plastic trees and vegetation!

AND there is no public space. The de Young Museum, opposite the Cal Academy, has one-third of its exhibit space open to the public - free. The Cal Academy has no public area, you can't even see much if you try to peek through the massive windows of the Nurembergesque-like building.

I feel better now. So, the Extreme Mammals exhibit is really interesting. It's not that big, it's in a room that I didn't even know was there, on the second floor, by the elevators.

Greg Farrington, Executive Director of the California Academy, said that this was the first new exhibit since the building opened 18 months ago.

As you enter the building and turn right, the first exhibit you see is on the first floor, a recreation of the world's largest land mammal, the 20 ton, 15-foot-tall Indricotherium.

Next to the Indricotherium is the world's smallest mammal, Batodonoides. 1.3 grams -- the weight of a dollar bill.

Upstairs is the main exhibit and our guide was Carol Tang, Director of Public Programs. I asked her why the focus on extreme mammals?

"We wanted to show people that there are many things about mammals that they probably didn't know. There is a much greater variety than most people think there is."

The main exhibit is a collection of skeletons and stuffed animals, nearly everything, including the fossils, are the genuine artifact, they aren't reproductions.

Here is a selection:

Ambulocetus, an ancestor of the whale.

Saber-toothed cat recovered from the tar pits of Southern California.

Elephant-shrew or sengi.

One of our guides was Academy scientist Galen Rathbun, who was part of a team that discovered a new species of elephant-shrew in 2008. These small insect eaters were nicknamed elephant-shrews because of their long nose. Interestingly, analysis of their DNA shows that they are indeed related to elephants but not to shrews.

Some of my notes:

- All mammals have three-bones in their ear.

- 2 mammal species lay eggs, the platypus and ecnida. Some extinct mammals also laid eggs.

-There are about 5400 mammal species. There are about 1,000 species of bats -- the most numerous mammal species.

- The Academy has 110,000 mammal specimens, some are preserved in -80 degree temperatures.

- About 1-2 dozen new mammal species are discovered every year.

- About 90% of insect species are undiscovered.

After touring the exhibit we were invited into the storage area which houses part of the Academy's massive collection of 26 million specimens, one of the world's largest natural history collections. This part of the building is as close to fire-proof as is possible.

The Academy lost its entire collection in 1906, in the devastating fire following a massive earthquake.

Here we are looking at what looks like rats on a stick but they are different sengi species. In addition to being related to elephants, they are also related to aardvarks and sea cows.

You can help finance the Academy's upcoming trip to Namibia, where Jack Dumbacher and Galen Rathbun will study a new species of sengi in the remote African desert: Discover and Protect a New Mammal Species: California Academy of Sciences

We also got to look in some of the drawers that contain extinct animals. One of the drawers contained passenger pigeons, which were very common in North America, they once numbered in the billions, the most common bird on the planet.

Unfortunately, they were delicious and very easy to catch. The last one died in captivity in 1914.

A good time to visit the Academy is on Thursday evening. The cost is just $12, less than half-price. There is a disco and usually a lecture too, plus you can buy a cocktail. No kids.

The third-Wednesday of every month is free. And there are free-days for locals, depending on your zip code: Free Admission Days at Academy of Sciences Via Zip Code - SFist

Here are some related links:

About the Academy: California Academy of Sciences

Events at California Academy of Sciences