I went to the Washington DC Zoo and the Smithsonian Museum of Natural History a few days ago with my mom - DC is close enough to home (1.5/2 hour drive) that it's nice to visit every once in a while! I particularly like the zoo because there is no admission cost (though there is no admission cost for the Smithsonian museums either). If I lived right in the area I'm sure I'd go there all the time to draw animals!
Below are just a couple (of many) photos I took while at the zoo, then below that are the sketches I did, none of which are anything special - it's all just practice. Sketching in pen is something I've only done a couple times before, so that was something relatively new for me. I'm a little rusty too because I have hardly drawn at all in the past two months due to being busy, and I don't feel like doing anything but relaxing with the free time I do have. I don't think any of these sketches exceeded 1 minute, I'd say most of them are around 30 seconds. I didn't sketch too much because it was hot, crowded, and I didn't have a stool or anything so any position I found myself drawing in was awkward and uncomfortable. I did quite a few of flamingo gestures because no one else was in that area, which gives me a much better peace of mind when it comes to sketching in public!