Well, when you consider the fact that Noah probably chose juvenile species rather than adult species when considering the larger mammals, it makes perfect sense.
People who question the Noah account in the Bible often picture grown animals, besides the fact that they simply disbelieve God’s Word.
I suggest a much bigger issue than whether the Ark could float the animals is whether it could float their supplies.
An elephant eats upwards of 300 pounds per day, so two adult elephants would consume upwards of 110 tons of food over the course of the arks journey.
That compares with perhaps 6 to 10 tons for the elephants themselves. Which gives us a ratio of perhaps 10x to 15x for the food supply as compared to the mass of the animals themselves.
Applying the ratio to people, which is perhaps more typical of many animals, particularly omnivores. 200 pound man requires about 2 pounds of dry food per day. 2 x 370 days = 740 pounds = food ratio of 3.7.
Horses eat about 3% of body weight per day, so food ratio of somewhere around 11.
Norm the ratio at a conservative 6:1 for food for all animals. The article unfortunately doesn’t seem to include the rather important number of the weight of the animals, only their quantity. But it would seem their food would weigh at least 6x as much as they did.
Also, if the entire earth was flooded, presumably the water the Ark was surrounded by was salty, which presents a rather critical logistical problem in itself.
Yes, baby tigers would be easier to handle; that is, if you could get them away from their mothers.