After time around Arenal, which wasn't ideal, Arturo had reserved a car in la Fortuna, and we drove to Cano Negro for a boat tour around the river going into the lake. We got to see nice wildlife, which while it mostly was birds, included some monkeys. The roads there were iffy at times.

the roads sucked

termites

those bats were awesome, almost impossible to distinguish from the bark

Eventually we got to our nice eco-hotel:

yummy dinner

The next morning, we went to Tenorio Volcano NP for a guided hike on muddy trails after a nice breakfast:

those leafcutter ants have been busy :)

very nice green-blue

you can see the volcanic water mixing with the river and causing the nice blue

Next, we went to a river to due tubing. It was a bit more extreme than normal tubing with lots of rocks to avoid, and low branches here and there, and we saw a huge tree on the way:

We then drove back to our hotel and went for a hike and night hike on celeste trail:

The 3rd day, we had to drive back to Fortuna but Arturo found a cool cave we could go visit on the way, and we got lucky to find 2 sloths while driving there. One had 3 toes, and the 2nd one had 2 toes and a baby:

Finally we got to the cave where we got a guide and photographer. That cave tour was really nice, it was quite tough to get through some holes, and challenging not to get my flashlight or camera under water in some crossings (some had to be done on my knees). That was definitely an experience you wouldn't get in many other places, and definitely not in the US where some tourists would get stuck or be physically unable to get through some passageways, and likely complain bitterly and/or slip, fall, and try to sue :-/
Thankfully this kind of stuff is still possible in Costa Rica, so that's what we did :)

the frog was guarding its eggs

you can see the eyes on those tadpoles

We then just had enough time to go back to La Fortuna for our transport to Monteverde.