<story><title>Crows have been shown to understand the concept of zero</title><url>https://www.quantamagazine.org/animals-can-count-and-use-zero-how-far-does-their-number-sense-go-20210809/</url></story><parent_chain><item><author>fossuser</author><text>There was a funny related example of the African Gray parrot Alex surprising the trainers by silently counting in his head.&lt;p&gt;They were training a younger parrot and trying to get the younger parrot to count to two by tapping twice.&lt;p&gt;Alex overheard the training and got impatient with the other bird. He yelled out “two” and then after two more taps “four” and then “six”.&lt;p&gt;The trainers were just expecting “two” each time.&lt;p&gt;It was this book: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.amazon.com&amp;#x2F;Are-Smart-Enough-Know-Animals&amp;#x2F;dp&amp;#x2F;0393353664&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.amazon.com&amp;#x2F;Are-Smart-Enough-Know-Animals&amp;#x2F;dp&amp;#x2F;0393...&lt;/a&gt;&lt;p&gt;The book is interesting and goes into how humans need to set up experiments properly to actually test non-human animals in ways that make sense (rather than just in some biased human way).&lt;p&gt;One quick example was testing tool use, the original experimenters left branches on the ground for the monkeys to use, but the monkeys can’t pick stuff up that’s flat on the ground since they’re normally in trees (their hands don’t have thumbs that move that way). When he redid the experiment with the tool raised they were able to grab and use it.&lt;p&gt;Same author also wrote Chimpanzee Politics and did this great video experiment: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;youtu.be&amp;#x2F;meiU6TxysCg&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;youtu.be&amp;#x2F;meiU6TxysCg&lt;/a&gt;</text></item></parent_chain><comment><author>rubyn00bie</author><text>A dog I live with, not technically mine, can count to at least three. She hates waiting in her harness before we go on walks, and has learned that I am ready to go after taking three poop bags. If I only pull two bags, she won’t come downstairs and wait by the door. If I pull the third bag, she immediately walks down the stairs. I noticed it the other day because I had two bags on me; so, she only heard me pull one bag and refused to walk downstairs. Then I pulled a second one, still nothing. Finally, I pulled the third one and she immediately trotted on down. Now that I’m aware of it, I’ve been paying attention and yep... she only ever comes down after hearing a third bag. I’ve been pretty shocked by it to be honest (in a good way)...</text></comment>
<story><title>Crows have been shown to understand the concept of zero</title><url>https://www.quantamagazine.org/animals-can-count-and-use-zero-how-far-does-their-number-sense-go-20210809/</url></story><parent_chain><item><author>fossuser</author><text>There was a funny related example of the African Gray parrot Alex surprising the trainers by silently counting in his head.&lt;p&gt;They were training a younger parrot and trying to get the younger parrot to count to two by tapping twice.&lt;p&gt;Alex overheard the training and got impatient with the other bird. He yelled out “two” and then after two more taps “four” and then “six”.&lt;p&gt;The trainers were just expecting “two” each time.&lt;p&gt;It was this book: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.amazon.com&amp;#x2F;Are-Smart-Enough-Know-Animals&amp;#x2F;dp&amp;#x2F;0393353664&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.amazon.com&amp;#x2F;Are-Smart-Enough-Know-Animals&amp;#x2F;dp&amp;#x2F;0393...&lt;/a&gt;&lt;p&gt;The book is interesting and goes into how humans need to set up experiments properly to actually test non-human animals in ways that make sense (rather than just in some biased human way).&lt;p&gt;One quick example was testing tool use, the original experimenters left branches on the ground for the monkeys to use, but the monkeys can’t pick stuff up that’s flat on the ground since they’re normally in trees (their hands don’t have thumbs that move that way). When he redid the experiment with the tool raised they were able to grab and use it.&lt;p&gt;Same author also wrote Chimpanzee Politics and did this great video experiment: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;youtu.be&amp;#x2F;meiU6TxysCg&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;youtu.be&amp;#x2F;meiU6TxysCg&lt;/a&gt;</text></item></parent_chain><comment><author>bsza</author><text>There was this horse named Clever Hans whose trick was that you could give him a math problem and he would tap out the answer with his hoof. Of course, his powers were fake, but the way he actually did it is brilliant.&lt;p&gt;When the number of taps approached the correct answer, his trainer became excited. Hans picked up on this and stopped right when the trainer&amp;#x27;s excitement reached its peak. The trainer had no idea this was happening. He was fooled by a horse.&lt;p&gt;&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Clever_Hans&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Clever_Hans&lt;/a&gt;</text></comment>