NMAP and PING showing different results

Hello,

I am hoping someone can explain why I'm seeing different results using the 2 commands.

Here is what I am seeing:

Code:[Thu May 14 10:00:40]
$ ping 10.1.208.77
PING 10.1.208.77 (10.1.208.77) 56(84) bytes of data.
64 bytes from 10.1.208.77: icmp_seq=1 ttl=127 time=52.0 ms
64 bytes from 10.1.208.77: icmp_seq=2 ttl=127 time=52.1 ms
64 bytes from 10.1.208.77: icmp_seq=3 ttl=127 time=52.1 ms
64 bytes from 10.1.208.77: icmp_seq=4 ttl=127 time=52.8 ms
64 bytes from 10.1.208.77: icmp_seq=5 ttl=127 time=52.5 ms
64 bytes from 10.1.208.77: icmp_seq=6 ttl=127 time=52.1 ms
64 bytes from 10.1.208.77: icmp_seq=7 ttl=127 time=52.0 ms
64 bytes from 10.1.208.77: icmp_seq=8 ttl=127 time=52.0 ms
64 bytes from 10.1.208.77: icmp_seq=9 ttl=127 time=51.9 ms
64 bytes from 10.1.208.77: icmp_seq=10 ttl=127 time=52.1 ms

--- 10.1.208.77 ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9011ms
rtt min/avg/max/mdev = 51.983/52.194/52.829/0.274 ms

[Thu May 14 10:00:57]
$ nmap -sP 10.1.208.77

Starting Nmap 6.40 ( http://nmap.org ) at 2020-05-14 10:01 EDT
Note: Host seems down. If it is really up, but blocking our ping probes, try -Pn
Nmap done: 1 IP address (0 hosts up) scanned in 3.01 seconds

[Thu May 14 10:01:08]
$ nmap -T5 -sP 10.1.208.77

Starting Nmap 6.40 ( http://nmap.org ) at 2020-05-14 10:01 EDT
Note: Host seems down. If it is really up, but blocking our ping probes, try -Pn
Nmap done: 1 IP address (0 hosts up) scanned in 1.50 secondsYou see with NMAP it is not showing the IP Address as being used but the PING command does. Why is this?

I have an alias for ping as follows:

Code:alias ping='ping -c 10'There are a few other IP Addresses that this is the same result and I"m trying to put my finger on as to why this is. Am I not to trust NMAP anymore as it seems to be missing some systems that are up?

Thank you in advance for your insight to this.